Category: Microsoft SQL Server

Technology – An Introduction to SQL Server Express

If you use SQL, several options are open to you, from the Enterprise editions down to SQL Server Express, a free version of Microsoft’s main RDBMS (Relational Database Management System), SQL Server. SQL Server is used to store information and access other information from multiple other databases. Server Express Edition is packed with features, such as reporting tools, business intelligence, advanced analytics, and so on.

SQL Server Express 2019 is the basic version of SQL Server, a database engine that can be deployed to a server, or you can embed it into an application. It is free and ideal for building desktops and small server applications driven by data. It is ideal for independent software developers, vendors, and those building smaller client apps.

The Benefits

SQL Server Express offers plenty of benefits, including:

  • Automated Patching – allows you to schedule windows to install important updates, to SQL Server and Windows automatically
  • Automated Backup – take regular backups of your database
  • Connectivity Restrictions – when you install Express on an Image Gallery-created Server VM installation, there are three options to restrict connectivity – Local (in the VM), Private (in a Virtual Network), and Public (via the Internet)
  • Server-Side Encryption/Disk Encryption – Server-side encryption is encryption-at-rest, and disk encryption encrypts data disks and the OS using Azure Key Vault
  • RBAC Built-In Roles – Role-Based Access Control roles work with your own custom rules and can be used to control Azure resource access.

The Limitations

However, SQL Express also has its limitations:

  • The database engine can only use a maximum of 1 GB of memory
  • The database size is limited to 10 GB
  • A maximum of 1 MB buffer cache
  • The CPU is limited to four cores or one socket, whichever is the least. However, there are no limits to SQL connections.

Getting Around the Limitations

Although your maximum database size is limited to 10 GB (Log Files are not included in this), you are not limited to how many databases you can have in an instance. In that way, a developer could get around that limit by having several interconnected databases. However, you are still limited to 1 GB of memory, so using the benefit of having several databases to get around the limitation could be wiped out by slow-running applications.

You could have up to 50 instances on a server, though, and each one has a limit of 1 GB memory, but the application’s development cost could end up being far more than purchasing a standard SQL license.

So, in a nutshell, while there are ways around the limits, they don’t always pay off.

SQL Server Express Versions

SQL Server Express comes in several versions:

  • SQL Server Express With Tools – this version has the SQL Server Database, and all the tools need for managing SQL instances, such as SQL Azure, LocalDB, and SQL Server Express
  • SQL Server Management Studio – this version contains the tools needed for managing SQL Server Instances, such as SQL Azure, SQL Express, and Local DB, but it doesn’t have SQL Server
  • SQL Server Express LocalDB –  if you need SQL Server Express embedded into an application, this version is the one for you. It is a lite Express version with all the Express features, but it runs in User Mode and installs fast with zero-configuration
  • SQL Server Express With Advanced Series – this version offers the full SQL Server Express experience. It offers the database engine, the management tools, Full-Text Search, Reporting Services, Express tools, and everything else that SQL Server Express has.

What SQL Server Express 2019 is Used For and Who Uses it

Typically, SQL Server Express is used for development purposes and to build small-scale applications. It suits the development of mobile web and desktop applications and, while there are some limitations, it offers the same databases as the paid versions, and it has many of the same features.

MSDE was the first SQL Server Data Engine from Microsoft, which was called Microsoft Desktop Engine. SQL Server Express grew when Microsoft wanted to build a Microsoft Access alternative to provide software vendors and developers with a path to the premium versions of SQL Server Enterprise and Standard.  

It is typically used to develop small business applications – web apps, desktop apps, or mobile apps. It doesn’t have all the features the premium versions have. Still, most small businesses don’t have the luxury of using a DBA (SQL Server database administrator), and they often don’t have access to developers who use DBAs either.

Lots of independent developers embed Server Express into the software, given that distribution is free. Microsoft has even gone down the road of creating SQL Server Express LocalDB. This lite version offers independent software vendors and developers an easier way of running the Server in-process in the applications and not separately. SQL Server Express is also considered a great starting point for those looking to learn about SQL Server.

Downloading SQL Server Express Edition 2019

SQL Server Express Edition 2019 is pretty easy to download, and you get it from the official Microsoft Website.

Once you have downloaded it onto your computer, follow the steps below to install it and set it up:

Step One

  • Right-click on the installation file, SQL2019-SSEI-Expr.exe.
  • Click on Open to get the installation process started – ensure that the user who is logged on has the rights needed to install software on the system. If not, there will be issues during the installation and setup.

Step Two

  • Now you need to choose which type of installation you need. There are three:
  • Basic – installs the database engine using the default configuration setup
  • Custom – this takes you through the installation wizard and lets you decide which parts to install. This is a detailed installation and takes longer than the basic installation
  • Download Media – this option allows you to download the Server files and install them when you want on whatever computer you want.
  • Choose the Custom installation – while the Basic is the easiest one, takes less time, and you don’t need to worry about the configuration as it is all done for you, the custom version allows you to configure everything how you want it.

Step Three

  • Now you have a choice of three package installation types:
  • Express Core – at 248 MB, this only installs the SQL Server Engine
  • Express Advanced – at 789 MB, this installs the SQL Server Engine, Full-Text Service, and the Reporting Services features
  • LocalDB – at 53 MB, this is the smallest package and is a lite version of the full Express Edition, offering all the features but running in user mode.

Step Four

  • Click on Download and choose the path to install Server Express to – C:\SQL2019
  • Click on Install and leave Server Express to install – you will see a time indicator on your screen, and how long it takes will depend on your system and internet speed.

Step Five

  • Once the installation is complete, you will see the SQL Server Installation Center screen. This screen offers a few choices:
  • New SQL Server Stand-Alone Installation or Add Features to Existing Installation
  • Install SQL Server Reporting Services
  • Install SQL Server Management Tools
  • Install SQL Server Data Tools
  • Upgrade From a Previous Version of SQL Server
  • We will choose the first option – click on it and accept the License Terms

Step Six

  • Click on Next, and you will see the Global Rules Screen, where the setup is checked against your system configuration
  • Click on Next, and the Product Updates screen appears. This screen looks for updates to the setup. Also, if you have no internet connection, you can disable the option to Include SQL Server Product Updates
  • Click on Next, and the Install Rules screen appears. This screen will check for any issues that might have happened during the installation. Click on Next

Step Seven

  • Click on Next, and the Feature Selection screen appears
  • Here, we choose which features are to be installed. As you will see, all options are enabled, so disable these:
  • Machine Learning Services and Language Extensions
  • Full-Text and Semantic Extractions for Search
  • PolyBase Query Service for External Data
  • LocalDB
  • Near the bottom of the page, you will see the Instance Root Directory option. Set the path as C:\Program Files\Microsoft SQL Server\

Step Eight

  • Click Next, and you will see the Server Configuration screen
  • Here, we will set the Server Database Engine startup type – in this case, leave the default options as they are
  • Click on the Collation tab to customize the SQL Server collation option
  • Click Database Engine Configuration to specify the Server authentication mode – there are two options:
  • Windows Authentication Mode – Windows will control the SQL logins – this is the best practice mode
  • Mixed Mode – Windows and SQL Server authentication can access the SQL Server.
  • Click on Mixed Mode, and the SQL Server login password can be set, along with a Windows login. Click on the Add Current User button to add the current user

Step Nine

  • Click on the Data Directories tab and set the following;
  • Data Root Directory – C:\Program Files\Microsoft SQL Server\
  • User Database Directory – C:\Program fees\Microsoft SQL Server\MSSQL.15.SQLEXPRESS\MSSQL\Data
  • User Database Log Directory – C:\Program fees\Microsoft SQL Server\MSSQL.15.SQLEXPRESS\MSSQL\Data
  • Backup Directory – C:\Program fees\Microsoft SQL Server\MSSQL.15.SQLEXPRESS\MSSQL\Backup

Step Ten

  • Click the TempDB tab and set the size and number of tempdb files – keep the default settings and click Next
  • Now you will see the Installation Progress screen where you can monitor the installation
  • When done, you will see the Complete Screen, telling you the installation was successful.

Frequently Asked Questions

Microsoft SQL Server Express Edition  2019 is popular, and the following frequently asked questions and answers will tell you everything else you need to know about it.

Can More than One Person Use Applications That Utilize SQL Server Express?

If the application is a desktop application, it can connect to all Express databases stored on other computers. However, you should remember that all applications are different, and not all are designed to be used by multiple people. Those designed for single-person use will not offer any options for changing the database location.

Where it is possible to share the database, the SQL Server Express Database must be stored in a secure, robust location, always be backed up, and available whenever needed. At one time, that location would have been a physical server located on the business premises but, these days, more and more businesses are opting for cloud-based storage options.

Can I Use SQL Server Express in Production Environments?

Yes, you can. In fact, some of the more popular CRM or accounting applications include Server Express. Some would tell you not to use it in a production environment, mostly because of the risks of surpassing your 10 GB data limit. However, provided you monitor this limit carefully, SWL Server Express Edition can easily be used in production environments.

Is SQL Server Express Edition Scalable?

There is a good reason why Microsoft allows you to download SQL Server Express Edition for free. It’s because, if it proves too small for your needs, at some point, you can upgrade to the premium SQL Server Standard version. While the Express Edition is limited and you are likely to outgrow it at some point, transferring your database over to the Standard version when the time comes is easy. Really, the Express version is just a scaled-down version of Standard. Any development you do on it is fully compatible with any other Edition of SQL Server and can easily be deployed.

Can I Use SQL Server Express in the Cloud?

Cloud computing is being adopted by more and more businesses and their applications. These days, many are now built in the cloud as web or mobile apps. However, when it comes to desktop applications, it is a slightly different story, as these need to be near the SQL Server Express Database to work properly. Suppose you host the database in the cloud but leave the application on the desktop. In that case, you are likely to experience poor performance, and you may even find your databases becoming corrupted.

You can get around this issue by running your application in the cloud, too, and this is easy using a hosted desktop (a hosted remote desktop service), which used to be known as a terminal service. In this case, the database and application reside on servers in the data center provided by the host and are remotely controlled by the users. As far as the user is concerned, it won’t look or feel any different from running on their own computer.

What Do I Get With SQL Server Express?

The premium SQL Server editions contain many features that you can also find in the free SQL Server Express Edition. Aside from the database engine, you also get:

Plus, the Express licensing allows you to bundles SQL Server Express with third-party applications.

What Isn’t Included?

There are a few things you don’t get in the Express edition compared to SQL Server Standard. For a start, Express edition has limits not found in the premium editions:

  • Each relational database can be no larger than 10 GB, but log files are not included as there are no limits on these
  • The database engine is limited to just 1 GB of memory
  • The database engine is also restricted to one CPU socket or four CPU cores, whichever is the lower of the two.
  • All the SQL Server Express Edition components must be installed on a single server
  • SQL Server Agent is not included – admins use this for automating tasks such as database replication, backups, monitoring, scheduling, and permissions.
  • Availability Groups
  • Backup Compression
  • Database Mirrors limited to Witness Only
  • Encrypted Backup
  • Failover Clusters
  • Fast recovery
  • Hot add memory and CPU
  • Hybrid Backup to Windows Azure
  • Log Shipping
  • Mirrored backups
  • Online Index create and rebuild
  • Online Page and file restore
  • Online schema change
  • Resumable online index rebuilds

Where Do I Find the SQL Server Express Edition Documentation?

You can find the relevant documentation at https://docs.microsoft.com/en-us/sql/?view=sql-server-ver15 and are urged to make good use of it. Refer to the documentation whenever you don’t understand something or want to learn how to do something new.

Microsoft SQL Server Express Edition 2019 is worth considering for small businesses, as it gives you a good starting point. As your business grows, you can upgrade to the premium versions without having to worry about learning a new system – you already know the basics, and your databases will transfer seamlessly over.

Related References

Erkec, Esat. 2020. “How to Install SQL Server Express Edition.” SQL Shack – Articles about Database Auditing, Server Performance, Data Recovery, and More. January 16, 2020.

shirgoldbird. n.d. “Microsoft SQL Documentation – SQL Server.” Docs.microsoft.com.

“What Is SQL Server Express and Why Would You Use It.” 2020. Neovera. March 27, 2020.

“What Is SQL Server Express Used For?” n.d. Your Office Anywhere.

“What Is SQL Server Express? Definition, Benefits, and Limitations of SQL Server Express.” 2017. Stackify. April 19, 2017.

Technology – An Introduction to SQL Server Express

Technology – The Difference Between Float Vs. Double Data Types

It would be incorrect to say that floating-point numbers should never be used as an SQL data type for arithmetic. I will stick to double-precision floating-point data types for SQL Server that are suitable for my requirements.

The double-precision floating-point data type is ideal for modeling weather systems or displaying trajectories but not for the type of calculations the average organization may use in the database. The biggest difference is in the accuracy when creating the database. You need to analyze the data types and fields to ensure no errors and insert the data values for maximum accuracy. If there is a large deviation, the data will not be processed during the calculation. If you detect incorrect use of the data type with double precision, you can switch to a suitable decimal or number type.

What are the differences between numeric, float, and decimal data types, and should they be used in which situations?

  • Approximate numeric data types do not store the exact values specified for many numbers; they store an extremely close approximation of the value
  • Avoid using float or real columns in WHERE clause search conditions, especially the = and <> operators

For example, suppose the data that the report has received is summarized at the end of the month or end of the year. In that case, the decimal data for calculation becomes integer data and is added to the summary table.

In SQL Server, the data type float _ n corresponds to the ISO standard with a value from n = 1 to 53. The floating-point data is approximated not by the data type’s value but by the range of what can be represented. Both float- and float-related numeric SQL types consist of a significant numeric value and an exponent, a signed integer that indicates the size of the numeric value.

And float-related numeric SQL data types are precise positive integers that define the number of significant digits and exponents of a base number. This type of data representation is called floating-point representation. A float is an approximate number, meaning that not all values can be displayed in the data type range because it is a rounded value.

You can’t blame people for using a data type called Money to store the money supply. In SQL Server, decimal, number, Money, and SmallMoney data types have a decimal place to store values. Precision means the total number of digits after the decimal point.

From a mathematical point of view, there is a natural tendency to use floats. People who use float spend their lives rounding up values and solving problems that shouldn’t exist. As I mentioned earlier, there are places where it makes sense to hover above the real, but these are for scientific calculations, not business calculations.

SmallMoney (2144783647, 4 bytes) We can use this data type for Money- or currency values. The double type can be used as a data type with real values for dealing with Money.

Type Description Memory bits Integer 0 1 null TinyInt allows integers 0 to 255 1 bytes TinyInt allows integers 32767 2 bytes Int allows integers 2147483647 4 bytes BigInt allows integers 9223372036854775807 8 bytes Decimal P is a precisely scaled number. The parameter p specifies the maximum total number of digits stored to the left or right of the decimal point. The data type low and upper range storage observations Real 340E 38 4 Bytes We can use float924 as an ISO synonym for real.

In MariaDB, the number of seconds has elapsed since the beginning of the 1970s (01-01) with a decimal accuracy of 6 digits (0 is the default). The same range of precision is the SQL Server type range (bytes) MariaDB type range size (bytes) Precision notes Date 0001 01-01-99.99 12: 31: 3 They cover the same range: Date 0.001-03-01 9.99912: 31 8: 0: 3 Round DateTime 0.01 0.1-02.9999 12: 31 8 0: 6 In MariaDB the value is near impossible to specify (see below). We can insert a value that requires fewer bits than that assigned to the null-bit pad on the left.

A binary string is a sequence of octets, not a character set, and the associated sorting is described by the binary data type descriptor. Decimal (p) is the exact numerical precision (p scale (n)) of a decimal number that is any number with a decimal point. A Boolean data type consists of different truth values (true, false, and boolean), and it supports unknown truth values, zeroes, and forbidden (not zero) constraints.

This syntax was deprecated in MySQL 8.0.17.7 and will be removed in future versions of MySQL: float (p) A floating-point number. MySQL uses the p-value to specify whether to use a float or a double due to the data type.

Creating data types in PostgreSQL is done with the create-type command. For example, the following commonly used data types are organized into categories with a brief description of the value range and memory size. The native data type is the text data type, the numeric data type, and the date/time Boolean data type.

To understand what floating-point SQL is and what numerical data types are, you need to study computer science a little. Floating-point arithmetic was developed when saving memory was a priority and was used as a versatile method for calculating large numbers. The SQL Prompt Code Analysis Rule (BP023) warns you when using Floating over Real data types. It introduces significant inaccuracies into the type of calculations that many companies do with their SQL Server data.

The difference between a float and a p is that a real float is binary (not decimal) and has an accuracy equal to or greater than the defined value.

The reason for this difference is that the SQL standard specifies a default from 0 to D. Still, the implementation is free to choose a default M. This means that an operation of this type will result in a result different from the result it would produce for MariaDB type if you use enough decimal places. It is important to remember that numerical SQL data types sacrifice precision ranges to approximate the names.

Technology – The Advantages of Using Microsoft SQL Server Integration Services

Microsoft SQL Server Integration Services (SSIS) is designed to combine the features of SQL Server with components of Enterprise Management System (EMMS) so that they can work together for enterprise solutions. Its core area of expertise is bulk/batched data delivery. As a SQL Server collection member, Integration Services is a logical solution to common organizational needs and current market trends, particularly those expressed by previously installed SQL Server users. It extends SSIS functionality, such as data extraction from external sources, data transformations, data maintenance, and data management. It also helps to convert data from one server into another.

There are several ways to use SSIS. External data sources may be data obtained from an outside source, such as a third-party application, or data obtained from an on-site database, such as a company’s own system. These external sources may contain transformations, including automatic updates, or specific requests, such as viewing certain data sources. There is also the possibility of data integration, in which different sets of data sources may be integrated into SSIS. Integration Services is useful for developing, deploying, and maintaining customer databases and other information sources.

The advantage of integrating SSIS with other vendors’ products is that it allows information to be made available within the organization and outside the organization. In other words, vendors can sell to internal users as well as external customers. Integration Services is usually sold as part of Microsoft SQL Server solutions. However, some companies may develop their own SSIS interfaces and build the entire communication layer independently.

There are two major advantages of using SSIS. The first is great support for telecommunication companies and enterprises that need to process a huge amount of information quickly and efficiently. Telecommunication companies use SSI to interface with other modules such as Microsoft Office applications, Sharepoint, and more. Another advantage of SSI is that integration provides access to all of the capabilities that a particular program or server has, such as data integration with Microsoft Visual Basic and JavaScript and the program’s full functionality or server. SSI is commonly used for web applications, particularly in sites that have to process large amounts of data quickly and efficiently.

There are a few disadvantages of using SSI, however. SSI is quite slow when compared to VBA and another object-oriented programming (OOP) methods. SSI also has some disadvantages in data quality, and the SSI interface can be difficult to use if one does not know how to code in the programming language. SSI is also limited in the number of programs and applications that can be integrated into one installation of SSI.

SSI is not only less flexible than VBA but can also be slower when compared to the traditional VBA script programs, as well. SSI can use a program or server with an SSI interface. Still, not all programs and servers that support SSI will provide an interactive command line for integration with a Microsoft SQL Server Integration Services database. In some cases, an interactive command line is necessary for SSI to use the DTS file necessary to process the data from an in-house database. SSI cannot connect to SSO independently but can use an in-house or external SSI file as a starting point for a connect and bind scenario.

For SSI to work effectively in a team-based development environment, the developer must understand and be familiar with the program. SSI has been designed with several different developer topologies and languages to write code and have it run in a timely manner while keeping track of files that might not be included with the program. A team-based development environment should be defined as a group effort where regular communication between team members and corporate databases can help this process along. SSI was designed to provide developers with the flexibility and control they need to maintain these relationships.

SSI can provide several advantages over VBA, including support for data structures in various programming languages and formats. This type of integration can save time for a business and is very cost-effective. SSI also provides several different programming interfaces and is flexible enough to use in any environment. If your company needs to use SSI, you must take the time to learn how to integrate it with your company’s database to ensure that the data structures used are compatible and effective for your application.

Technology – Can SQL Server Run On Linux?

Microsoft SQL Server provides organizations with industry-leading data capabilities, enhanced security, performance, and total cost of ownership. Unfortunately, up until 2017, SQL Server could only run on a windows ecosystem.

This was a huge pain point for many SQL server customers who preferred the Linux system over Windows for performance, security, and manageability. They had to run a separate MS Windows system just to support the SQL server! Not running MSQL Server on a Linux ecosystem became a friction point for many of these businesses.

Looking forward, can SQL server run on Linux? Yes. It’s now possible to run MSSQL Server on a Linux system. In 2017, Microsoft released SQL Server 2017, which could now run on Windows, Linux, and Docker containers. This was an exciting move by Microsoft, which seemed more focused on bringing its tools to wherever its users were.

Running SQL Server On Your Favorite Platform

MSSQL Server users can now install the relational database engine on an enterprise Linux ecosystem. Some of the Linux distributions which support SQL Server include:

  • Red Hat Enterprise 7.3+,
  • SUSE Enterprise V12 SP2+,
  • Ubuntu 16.04+
  • Docker (1.8+)

This cross-platform integration was made possible by a cool technology known as the SQL Platform Abstraction Layer (SQLPAL). Ideally, the Platform Abstraction Layer (PAL) created a more secure virtual OS layer that allowed the SQL Server to run efficiently on a Linux system without compromising its functionality.

This seamless cross-platform integration meant that Microsoft developers could maintain all vital SQL Server functions without the need to port the tens of millions of lines of MSSQL Server’s code to Linux.

Why Should I Run SQL Server on Linux?

Wondering if you should run SQL Server on Linux? Here are a few benefits:

  • Reduced Operating Cost due to a seamless cross-platform licensing model
  • Enterprise-ready features
  • Enhanced SQL server performance on Linux
  • Faster installation and maintenance

Conclusion

It’s now possible and super-easy to run Microsoft SQL Server on a Linux system. Today, millions of organizations run SQL Server on Linux OS, which has cut the cost and time to run and maintain their relational database engine. In the end, the cross-platform MSSQL Server integration on a Linux ecosystem removes the barrier to entry for organizations that prefer Linux to Windows.

Technology – What Are The SQL Minus and Except Clauses

Structured Query Language (SQL) is the de-facto query language used in most database management systems (DBMS) such as Oracle and Microsoft SQL Server. This domain-specific language is used in programming to query and return the desired data from a database. We use SQL to write queries that declare what data to expect from a dataset without really indicating how to obtain it. We can also use SQL to update and delete information from a database.

Ideally, in a relational database management system, the database usually runs on the “back end” side of a server in its structured form. By itself, this data is hard to interpret. So, users often have programs on a client computer that help to manipulate that data using rows, columns, fields, and tables. These programs are designed to allow users to send SQL statements to the server. The server then processes these statements by filtering data from the enormous, complex databases and returns results to the user.

Each query begins with finding the data needed then refining it down into something that can be processed and understood easily. To do this, you must use an organized set of operations to get meaningful data from a dataset. This article will explore the Minus Vs except SQL clauses to help you write optimized queries that run fast across various DBMS.

SQL EXCEPT clause

The SQL EXCEPT clause is one of the most commonly used statements that work together with two SELECT statements to return unique rows from a dataset. The SQL EXCEPT combines two SELECT statements to return the row that is present in the first select statement and not in the second.

If you’ve noticed, most SQL clauses do the same thing represented in standard spoken language. For instance, exception literally means not included. SQL EXCEPT is also very similar to the same concept.

The EXCEPT statement returns the distinct row from the left input query that is not output by the right input query. I.e., Returns the resultant rows that appear in query_expression_1 and not in query_expression_2.

SQL EXCEPT Clause Example

Consider a simple situation where you have two tables, one with dog names and the other one with cat names.

Cats Data Set

+———+———–+

| CatId | CatName |

|———+———–|

| 1 | Boss |

| 2 | Scarlet |

| 3 | Fluffy |

| 4 | Fluffy |

+———+———–+

Dogs Data Set

+———+———–+

| DogId | DogName |

|———+———–|

| 1 | Yelp |

| 2 | Woof |

| 3 | Boss |

| 4 | Boss |

+———+———–+

Using the SQL Except statement, we can filter the dataset and return only the distinct rows from the left SELECT query that have not been returned by the SELECT query on the right side of the EXCEPT statement.

An example SQL syntax query would look like this:

SELECT CatName FROM Cats

EXCEPT

SELECT DogName FROM Dogs;

In a typical scenario, a client program will send this query to the “back-end” server. This statement is then processed and only returns the values available in the “cats” dataset that don’t appear in the “dogs” dataset. When two rows are similar, as is the case with “fluffy,” only one row is returned. This is because the SQL query only returns distinct rows.

Here’s the result of the above query:

+———–+

| CatName |

|—————|

| Fluffy |

| Scarlet |

+————– +

Common SQL Except Rules
  • You must have the same number of columns in both queries
  • The column order must be the same in all queries
  • The column data types must be compatible with each other. The data types really don’t have to be the same, but they MUST be comparable through implicit conversion.
  • The EXCEPT statement returns all records from the 1st SELECT statement not available in the second SELECT statement
  • The EXCEPT operator in the SQL server is similar to the MINUS operator in Oracle.
  • MySQL does not support SQL Except clause. The workaround is to use the LEFT JOIN clause when using MySQL.

SQL MINUS Clause

MINUS operator does the same thing as the EXCEPT clause. But unlike the EXCEPT clause, the MINUS operator is only supported by Limit number of databases:

Database NameMinusExcept
Amazon RedshiftNoYes
VQL (denodo)YesNo
ElasticsearchYesNo
MariaDBYesYes
IBM Db2NoYes
Microsoft SQL ServerNoYes
MongoDBNoNo
MySQLNoNo
OracleYesNo
PostgreSQL No Yes
SOQL (salesforce)NoNo
snowflakeYesYes
SQLiteNoYes

The MINUS operator compares two queries and only returns the rows present in the first dataset but are not output by the second set. The result usually contains the distinct rows available in the left Select statement that aren’t included in the results of the right select statement.

Here is a typical MINUS syntax:

SELECT column_list_1 FROM T1

MINUS

SELECT column_list_2 FROM T2;

Common Oracle Minus Operator Rules

For MINUS operator to work, the dataset must conform with rules similar to those of SQL EXCEPT clause:

  • The data type of corresponding columns must be similar (Either Numeric or Character)
  • The order and number of columns must be the same.
  • The column used for ordering can be defined by the column number.
  • Duplicates are automatically eliminated in the final result.

Conclusion

The Minus Vs Except SQL Clause comparison can be confusing for many people. These two clauses are synonymous with each other and have similar syntax and results. Both Minus and Except help users skim through datasets to identify unique rows available only in the first SELECT query and not returned by the second SELECT query.

Technology – Microsoft SQL Server Temp Table Types

There are a few basics to get to know when it comes to Microsoft SQL server temp table types. For the SQL server, temp table types global-local are two main types that are employed. DB developers are known for using temporary tables, but at the same time, they also may not be keen to go outside of their comfort zone or look at every single thing that they can do.

Temporary tables can actually accomplish quite a lot. Temporary tables can improve not only the performance of code but its ability to be maintained as well. At the same time, when things start to go left, it can be a massive pain for the DBA and developer, making everything go way slower than would be preferable.

So what do temporary tables do? A lot of the clue is in the name. They are most frequently used to provide users with the workspace they require for intermediate results when they are busy processing data inside a procedure or a batch. Temporary tables can help pass data from between stored procedures to a table-valued function or in Table-valued parameters, sending read-only tables to SQL server routines from applications and passing read-only temporary tables in turn for parameters. At the end of their use, automatic discarding is a process, so the user does not have to do anything.

Temporary tables include a variety, but the main ones you need to know are local temporary tables and global temporary tables (with a special tip of the hat to persistent temporary tables and table variables). Both global and local temporary tables start with their own symbol, which we will get into down further on.

Temporary tables are the superior pick to table variables when conducting complex processing for temporary data or using more data in them that isn’t as small. Users can utilize global or local temporary tables in SQL Server. Still, the server won’t store their definition permanently when it comes to database catalog views, which can cause problems with visibility and scope. While global tables can be seen by all sessions, the local tables can be seen in the current session alone.

Microsoft SQL Server Temp Table Types

SQL Server HAS for two types of temporary tables:

  • Local Temporary Tables, which are visible only in the current session
  • Global Temporary Tables, which are visible to all sessions

Local Temporary Tables (LTT)

  • Starts with the symbol ‘#’
  • Created with a CREATE TABLE statement, table name prefixed with a number sign (#numbersigntablename)
  • Visible in current sessions, cannot be accessed from later sessions
  • When created in a stored procedure, it will be automatically dropped when the procedure finishes
  • Nested stored procedures are needed to reference this LTT
  • Global Temporary Tables Can’t be referenced using stored procedure/application of the stored procedure to make LTT

Global Temporary Tables

  • Starts with the symbols ‘##’
  • Created with a CREATE TABLE STATEMENT, the table name is prefixed using two number signs (##twosignstablename)
  • Visible to all connections/sessions on SQL, can be used from other sessions
  • A global temporary table is dropped automatically as the table-creating session, and the other session’s final active Transact-SQL statement ends

Whether you’re familiar with temporary tables or new to them, the great news is that there’s always something more to learn about this subject as well as coding, programming, and computers. Temporary tables are easy to get the hang of once you get into working with them a bit. Thanks for reading, and happy learning!

SQL Server Length Function Equivalent

The purpose of the Length function in SQL

The SQL LENGTH function returns the number of characters in a string. The LENGTH function is available in many Database Management Systems (DBMS).

The LENGTH Function Syntax

  • LENGTH(string)

LENGTH Function Notes

  • If the input string is empty, the LENGTH returns 0.
  • If the input string is NULL, the LENGTH returns NULL.

Length Function Across Databases

When working as a technical consultant, one has to work with customer’s databases and as you move from one database to another you will find that the function commands may vary–assuming the database has an equivalent function.

Working with VQL and SQL Server got me thing about the LENGTH() function, so, here is a quick references list, which does include the SQL Server.  

IBM DB2

  • LENGTH( )

IBM Informix

  • CHAR_LENGTH() Or CHARACTER_LENGTH()

MariaDB

  • LENGTH( )

Microsoft SQL Server

  • LEN( )

MySQL

  • CHAR_LENGTH() Or CHARACTER_LENGTH()

Netezza

  • LENGTH( )

Oracle

  • LENGTH( )

PostgreSQL

  • CHAR_LENGTH() Or CHARACTER_LENGTH()

SOQL (SalesForce)

  • SOQL has no LENGTH function

VQL (Denodo)

  • LEN( )

What is the difference between left join and left outer join in SQL

  • Left Outer Join Relationship

When working with different databases syntax can cause questions and confusion.  Recent having been asked what the difference was between a left join and a left outer join, a subject which I hadn’t thought about in a while, I thought a simple explanation might be in order.   Actually, there is no difference between a left join and a left outer join, other than syntax.  Both perform the exact same operation in SQL, where the Left (Outer) Join will retain those rows for which there was a match in both tables and, also, retain those rows which exist only in the left (controlling) table of the join.