Temporary Table in MySQL

In MySQL, a temporary table is a table that is created and exists only for the duration of a database session. Temporary tables are useful for storing intermediate results within a single database connection or for storing session-specific data, such as user-specific information.

Syntax

To create a temporary table in MySQL, you can use the following syntax:

CREATE TEMPORARY TABLE temp_table_name (
  column1 datatype1 constraints,
  column2 datatype2 constraints,
  ...
);

The CREATE TEMPORARY TABLE statement is followed by the name of the temporary table, and then a list of columns with their datatypes and any constraints.

Example

Here's an example of creating a temporary table in MySQL:

CREATE TEMPORARY TABLE temp_sales (
  id INT PRIMARY KEY AUTO_INCREMENT,
  customer_name VARCHAR(255),
  purchase_amount FLOAT
);

This creates a temporary table called temp_sales with three columns, id, customer_name, and purchase_amount. The id column is the primary key, and it is auto-incremented.

Explanation

In the example above, we created a temporary table named temp_sales with three columns. The id column is the primary key and is auto-incremented, which means that MySQL will automatically generate unique values for this column when new rows are inserted into the table. The customer_name and purchase_amount columns are used to store customer names and the amount of their purchase, respectively.

Use

Temporary tables can be used for a variety of purposes, such as:

• Storing intermediate results of a complex query to improve performance
• Storing session-specific data that is not relevant outside of a single database connection
• Storing data for complex reports or queries that require multiple joins or subqueries

Important Points

• Temporary tables are only visible within the current session and are automatically dropped when the session is terminated.
• In MySQL, temporary tables have a # prefix in their name. For example, if you create a temporary table named temp_sales, MySQL will actually name the table #temp_sales.
• Temporary tables can have the same structure as permanent tables, but they are not affected by transactions.
• Temporary tables can have indexes, constraints, and triggers, just like permanent tables.

Summary

In this tutorial, we discussed temporary tables in MySQL. We covered the syntax for creating a temporary table, an example of creating a temporary table, an explanation of the example, the use cases for temporary tables, and important points to keep in mind when using temporary tables. With this knowledge, you can use temporary tables in your MySQL database to store session-specific data and improve performance.