MYSQL if a select query returns 0 rows then another select query?

Question

if select * from table where x=1 returns 0 rows, then I need select * from table where x=2 [or some other query]. Is it possible to do this in a si

Answer 1

This appears to work from a quick test I just did and avoids the need to check for the existence of x=1 twice.

SELECT SQL_CALC_FOUND_ROWS *
FROM mytable
WHERE x = 1

UNION ALL

SELECT *
FROM mytable
WHERE 
FOUND_ROWS() = 0 AND x = 2;

Edit: Following your clarification to the question obviously the 2 queries will need to be UNION compatible for the above to work.

The answer to your updated question is No. This is not possible in a single query. You would need to use some conditional procedural logic to execute the desired query.