Best way to test if a row exists in a MySQL table
exists, mysql, performance, sql
Solution
You could also try `EXISTS`:
SELECT EXISTS(SELECT * FROM table1 WHERE ...)
and per the documentation, you can `SELECT` anything.
Traditionally, an EXISTS subquery starts with SELECT *, but it could begin with SELECT 5 or SELECT column1 or anything at all. MySQL ignores the SELECT list in such a subquery, so it makes no difference.
Problem
I'm trying to find out if a row exists in a table. Using MySQL, is it better to do a query like this: ``` SELECT COUNT(*) AS total FROM table1 WHERE ... ``` and check to see if the total is non-zero or is it better to do a query like this: ``` SELECT * FROM table1 WHERE ... LIMIT 1 ``` and check to see if any rows were returned? In both queries, the WHERE clause uses an index.