How to Efficiently Delete Data Across Multiple MySQL Tables with a Single Query?

Deleting Data from Multiple Tables with a Single Query in MySQL

When working with multiple tables related by a common field, it may be necessary to delete information about a user from all tables simultaneously. Rather than executing multiple DELETE statements, this query explores the possibility of performing the deletion in a single query.

The proposed query involves using multiple DELETE statements separated by semicolons:

DELETE FROM table1 WHERE user_id='$user_id';
DELETE FROM table2 WHERE user_id='$user_id';
DELETE FROM table3 WHERE user_id='$user_id';
DELETE FROM table4 WHERE user_id='$user_id';

However, according to the MySQL documentation, this is not the optimal approach. The documentation suggests utilizing the following syntax:

DELETE t1, t2 FROM t1 INNER JOIN t2 INNER JOIN t3
WHERE t1.id=t2.id AND t2.id=t3.id;

This query allows for the deletion of rows from multiple tables based on a specified condition in the WHERE clause. In this case, the condition would be t1.user_id='$user_id'.

Utilizing this approach simplifies the deletion process and ensures that the data from all relevant tables is removed simultaneously.

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