What is the purpose of creating a temporary table in SQL?
The purpose of creating a temporary table in SQL is to create a temporary table in the database that only exists for the current session, and automatically gets deleted after the session ends. The use of temporary tables can include:
- Temporary data storage: Temporary tables can be used to store temporary data, such as storing intermediate results in complex queries or data processing for future use.
- Break down complex queries: For complex queries, you can use temporary tables to split them into multiple simple steps and store intermediate results in temporary tables to improve query performance and readability.
- Caching the result set: In some cases, when a query result set may be reused multiple times and the computation is time-consuming, the result set can be stored in a temporary table. This allows subsequent queries to directly retrieve the result from the temporary table without the need for repeated calculations.
- Simulation of actual table: In some cases, it may be necessary to perform some testing or experiments on the actual table, but manipulating the actual table could have irreversible effects. Temporary tables can be used to simulate the structure and data of the actual table for testing and experimentation.
In conclusion, the main purpose of temporary tables is to provide temporary storage space for storing and processing data, and they are automatically cleared after the session ends without causing any permanent impact on the actual database.
