MySQL error in file: /engine/init.php at line 304

Error Number: 1021

The Error returned was:
Disk full (/tmp/#sql_564_0.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")

SQL query:

SELECT category, COUNT(*) AS count FROM dle_post WHERE approve=1 AND date < '2020-07-16 05:54:34' GROUP BY category