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Are temporary tables supported by MySQL?
MySQL has a feature to create a special table called a Temporary Table that allows us to keep temporary data. This table is visible and accessible only for the current session. MySQL deletes this table automatically as long as the current session is closed or the user terminates the connection.
Where are MySQL temporary tables stored?
An internal temporary table can be held in memory and processed by the MEMORY storage engine, or stored on disk by the InnoDB or MyISAM storage engine. If an internal temporary table is created as an in-memory table but becomes too large, MySQL automatically converts it to an on-disk table.
How many times can a temporary table be used in a single stored procedure?
8 Answers. Nope. Independent instances of the temporary table will be created per each connection.
What is the use of temporary table in MySQL?
In MySQL, a temporary table is a special type of table that allows you to store a temporary result set, which you can reuse several times in a single session. A temporary table is very handy when it is impossible or expensive to query data that requires a single SELECT statement with the JOIN clauses.
Are temp tables automatically deleted?
Temporary tables are similar to permanent tables, except temporary tables are stored in tempdb and are deleted automatically when they are no longer used. There are two types of temporary tables: local and global. They differ from each other in their names, their visibility, and their availability.
When to drop temporary table in MySQL stored procedure?
By default MySQL config variable sql_notes is set to 1. That means that DROP TEMPORARY TABLE IF EXISTS performance; increments warning_count by one and you get a warning when a stored procedure finishes. You can set sql_notes variable to 0 in my.cnf or rewrite stored procedure like that:
When to use the temporary keyword in MySQL?
You can use the TEMPORARY keyword when creating a table. A TEMPORARY table is visible only within the current session, and is dropped automatically when the session is closed.
How are temporary tables created in stored procedures?
If a local temporary table is created in a stored procedure or application that can be executed at the same time by several users, the Database Engine must be able to distinguish the tables created by the different users. The Database Engine does this by internally appending a numeric suffix to each local temporary table name.
How to check if a temporary table exists in MySQL?
If the temporary table exists, the @table_exists variable is set to 1, otherwise, it sets to 0. This statement calls the check_table_exists to check if the temporary table credits exists: