Create a Temp Table in SQL Server

Hello, Dev! Are you looking for an efficient way to create temporary tables in SQL Server? If so, you’ve come to the right place. In this article, we’ll discuss the basics of creating temporary tables in SQL Server and provide you with a step-by-step guide on how to create them. So, let’s get started!

What is a Temp Table?

A temporary table is a table that is created and used for storing data temporarily. The data in a temporary table is only available for the duration of the connection or session that created it. After the connection is closed or session ends, the temporary table is automatically dropped, and the data stored in it is lost. Temporary tables are often used to provide a temporary storage area for intermediate results in a complex query or to store data that needs to be manipulated before being inserted into a permanent table.

The Advantages of Using Temp Tables

There are several advantages to using temporary tables in SQL Server:

How to Create a Temp Table in SQL Server

Creating a temporary table in SQL Server is a simple process. Here’s how you can do it:

Step 1: Creating the Table

The first step in creating a temporary table is to use the CREATE TABLE statement. However, instead of specifying the database where the table will be created, you need to use the # symbol followed by the table name to indicate that it is a temporary table. Here’s an example:

CREATE TABLE #TempTable(Column1 INT,Column2 VARCHAR(50));

Step 2: Adding Data to the Table

After creating the table, you can add data to it using the INSERT INTO statement. Here’s an example:

INSERT INTO #TempTable (Column1, Column2)VALUES (1, 'Dev'), (2, 'Journal'), (3, 'Article');

Step 3: Retrieving Data from the Table

You can retrieve data from the temporary table using a regular SELECT statement. Here’s an example:

SELECT Column1, Column2FROM #TempTableWHERE Column1 = 1;

Step 4: Dropping the Table

Once you’re done using the temporary table, you can drop it using the DROP TABLE statement. Here’s an example:

DROP TABLE #TempTable;

FAQs

What is the difference between a temporary table and a table variable?

A temporary table is created in the tempdb database and can be accessed by multiple users, whereas a table variable is created within the scope of a single user-defined function or stored procedure and cannot be accessed outside of that scope.

Can I create indexes on a temporary table?

Yes, you can create indexes on a temporary table to improve query performance.

Do temporary tables persist after a server restart?

No, temporary tables are created in the tempdb database, which is recreated every time SQL Server is restarted, so temporary tables are not persisted after a server restart.

Can a temporary table be referenced in a subquery?

Yes, you can reference a temporary table in a subquery. However, you need to make sure that the temporary table is created before the subquery is executed.

What is the naming convention for temporary tables?

The naming convention for temporary tables is to use the # symbol followed by the table name. For example, #TempTable.