mysql - 无法正确获取Mysql触发语句

Question

有人可以告诉我这个触发语句有什么问题吗？

DELIMITER //

CREATE TRIGGER something AFTER INSERT ON sometable
FOR EACH ROW
BEGIN
DECLARE var INT DEFAULT 0;
SET var = SELECT COUNT(*) FROM anothertable;
IF var=0 THEN
INSERT INTO anothertable values(`x`,`y`,`z`);
END IF;
END//

我不断收到错误消息，说我有语法错误...

Answer 1

尝试将 SELECT 语句放在括号内:

DELIMITER //

CREATE TRIGGER something AFTER INSERT ON sometable
FOR EACH ROW
BEGIN
    DECLARE var INT DEFAULT 0;
    SET var = (SELECT COUNT(*) FROM anothertable);
    IF var=0 THEN
        INSERT INTO anothertable values('x','y','z');
   END IF;
END//