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How to create and use table variables in T-SQL Part one of a three-part series of blogs
Table variables allow you to hold rows of data in temporary storage, without any processing overhead. Read this blog to add this technique to your SQL armoury! Table Variables in SQL (this blog) Worked Example of a Table Variable Pros and cons of table variables This blog is part of our full online SQL tutorial. For a more personal experience, have a look at our SQL training courses for businesses.

How to create and use table variables in T-SQL

Part one of a three-part series of blogs

Table variables allow you to hold rows of data in temporary storage, without any processing overhead. Read this blog to add this technique to your SQL armoury!

This blog is part of our full online SQL tutorial. For a more personal experience, have a look at our SQL training courses for businesses.

Posted by Andy Brown on 08 February 2013

Table Variables in SQL

I've previously blogged about temporary tables as part of our grand online SQL training series of blogs - it's time now to look at their sibling, table variables.

I'll discuss later the pros and cons of table variables, but it's largely a matter of personal preference whether you use them instead of or as well as temporary tables. I like table variables because you never have to worry whether they already exist when you create them!

Syntax of Temporary Variables

In a previous blog I showed that you can declare variables as follows:

DECLARE @VariableName VariableType

where VariableType can be any of the standard data types in SQL. So the following are examples of variables:

DECLARE @LifeAnswer int = 42

DECLARE @AlternativeAnswer varchar(50) = 'Forty-two'

However, you can also declare a variable to refer to an entire table. The syntax for this is as follows:

DECLARE @TableName TABLE (

FirstColumn datatype,

...

LastColumn datatype

)

Why would you want to do this? Let's look at a worked example, showing how you could solve it with and without a table variable.

Parts of this blog
Table Variables in SQL (this blog) Worked Example of a Table Variable Pros and cons of table variables

Some other pages relevant to the above blogs include:

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