SELECT IF(SUM(a) >= 4, 'OK', 'ERROR') FROM table_1;
IF(SUM(a) >= 4, 'OK', 'ERROR')
OK
SELECT IF(SUM(a) >= 5, 'OK', 'ERROR') FROM table_2;
IF(SUM(a) >= 5, 'OK', 'ERROR')
OK
SELECT IF(SUM(a) > 0, 'OK', 'ERROR') FROM table_3;
IF(SUM(a) > 0, 'OK', 'ERROR')
OK
SELECT IF(SUM(a) > 0, 'OK', 'ERROR') FROM table_4;
IF(SUM(a) > 0, 'OK', 'ERROR')
OK
DROP EVENT two_sec;
SELECT IF(TIME_TO_SEC(TIMEDIFF(ENDS,STARTS))=6, 'OK', 'ERROR') FROM INFORMATION_SCHEMA.EVENTS WHERE EVENT_SCHEMA=DATABASE() AND EVENT_NAME='start_n_end' AND ENDS IS NOT NULL;
SELECT IF(LAST_EXECUTED-ENDS < 3, 'OK', 'ERROR') FROM INFORMATION_SCHEMA.EVENTS WHERE EVENT_SCHEMA=DATABASE() AND EVENT_NAME='start_n_end' AND ENDS IS NOT NULL;