What is a temporary table and what is it used for?

A temporary table is a table that exists only during the duration of the current session or transaction.

Purpose:

• Temporary storage of intermediate data: Used to save the results of a complex query or to process data step-by-step.
• Performance improvement: A query using a temporary table can be faster than executing a complex query directly, especially if intermediate data is reused multiple times.
• Breaking down complex queries: Allows splitting a large and hard-to-read query into smaller, manageable parts.
• Working with a subset of data: A temporary table may contain only the necessary subset of data for a specific operation.

Creating a temporary table (example for SQL):

-- Creating a temporary table
CREATE TEMPORARY TABLE temp_customers AS
 SELECT customer_id, customer_name
 FROM customers
 WHERE registration_date >= '2023-01-01';

-- Using the temporary table
SELECT COUNT(*)
FROM temp_customers;

-- The temporary table will be automatically deleted at the end of the session