![]() Temporary tables are removed automatically when your application is terminated. If you develop an application that uses a connection pooling or persistent connections, it is not guaranteed that the The DROP TEMPORARY TABLE statement, you will get an error message stating that the table you are trying to drop is unknown.įor example, to remove the tempProductsAboveAvgPrice temporary table, you use the following statement:ĭrop temporary table tempProductsAboveAvgPrice If you try to drop a permanent table with However it is good practice to use the DROP TEMPORARY TABLE statement insteadīecause the DROP TEMPORARY TABLE statement removes only temporary tables, not the permanent tables. You can use the DROP TABLE statement to remove a temporary table. The best way to drop a MySQL Temporary Table Permanent table accidentally), it is recommended that you always prefix the name of a Temporary Table with tmp_ or temp_ in order to differentiate it To minimize any confusion or potential problems (e.g. Retrieves data from the customers Temporary Table, not the existing permanent customers table. When you select data from the customers table, it Northwind Traders database, the existing permanent table customers will become invisible for any queries. For example, if you create a Temporary Table called customers in Permanent table, the existing table becomes hidden until the temporary table is dropped. If the Temporary Table you create has the same name as an existing Note that you also can use the DROP TABLE statement to explicitly drop a Temporary Table.Ī Temporary Table is created inside the database that the session is connected to. In other words, the Temporary Table isĪutomatically removed on closure of database connection. Which one is more efficient - carry 1 brick each time from A to B for 10 times, or put the 10 bricks in a trolley andĪs of MySQL version 5.7, MySQL TEMPORARY tables have the following limitations:Ī Temporary Table is visible only to the current session, and is dropped automatically when the session is closed. Suppose you need to moveġ0 bricks from point A to point B. In one go by using a single set-based query such as cross update query or bulk insert query. Consider to prepare the data in a Temporary Table, do all the works upfront, and when the data is ready, add the data to some table This is very useful in situations where you need to repeatedly perform the sameĪction in a database. ![]() You need to manipulate (add unique IDs aka auto number, update, insert, or delete) the result of a query in a temporary place, without needing toĬreate permanent tables in a production environment for data manipulation.Immediate result set is needed because the result set is required more than once in different queries, therefore eliminates the need to run Pieces of small queries with the use of Temporary Tables). The temporary table's dataset is needed in other queries because it can dramatically reduce the complexity of the entire work (e.g. Life easier if they need to maintain your queries or customize for some other uses. Therefore, if you ever find you frequently write complex SQL queries, consider using Temporary Tables to simplify your work. For example, you need to retrieve a bunch of data from multiple tables with join, union, group by, etc., then you need to Temporary Table offers definite advantages when it's used to hold data returned from a very complex query (so very expensive to create)įor temporary use. ![]() The Divide and Conquer rules - this is the single most attractive advantage of using MySQL Temporary Table.
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