MySQL Error Occurred

Error Message:
1021: Disk full (/var/mysqltmp/#sql_6b78_21.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")

SQL:
SELECT * FROM cubecart_searches WHERE MATCH (keywords) AGAINST ('four by veronica roth' IN BOOLEAN MODE) AND status='0' order by rand() LIMIT 10