zaho_account表是账户总表,zaho_tihuo_code是关联的子表。在zaho_account表中有一个字段:a_code_used,表示该账号下有多少条code记录。

DROP TRIGGER IF EXISTS `tihuo_code_insert`;

CREATE TRIGGER `tihuo_code_insert` AFTER INSERT ON `zaho_tihuo_code`

FOR EACH ROW BEGIN

UPDATE `zaho_account` SET a_code_used=a_code_used+1 WHERE a_id=NEW.account_id;

END//

-- 删除

DELIMITER //

DROP TRIGGER IF EXISTS `tihuo_code_delete`;

CREATE TRIGGER `tihuo_code_delete` AFTER DELETE ON `zaho_tihuo_code`

FOR EACH ROW BEGIN

UPDATE `zaho_account` SET a_code_used=a_code_used-1 WHERE a_id=OLD.account_id;

END//

-- 附赠一个把历史数据更新到a_code_used字段的SQL

UPDATE zaho_account a SET a_code_used=(select count(1) from zaho_tihuo_code where account_id=a.a_id)

关于MySQL触发器统计子表数量,本文就介绍这么多,希望对您有所帮助!

03-14 00:07