COUNT(*) van meerdere tabellen in MySQL

U kunt dit doen door subquery's te gebruiken, één subquery voor elke tableCount:

SELECT
  (SELECT COUNT(*) FROM table1 WHERE someCondition) as table1Count, 
  (SELECT COUNT(*) FROM table2 WHERE someCondition) as table2Count,
  (SELECT COUNT(*) FROM table3 WHERE someCondition) as table3Count