MySQL：比较两个数据表不同部分

简单比较

1、SELECT * FROM t2 WHERE id NOT IN (SELECT id FROM t1);

2、SELECT * FROM t2 WHERE NOT EXISTS(SELECT * FROM t1 WHERE t1.id=t2.id);

3、SELECT t2.* FROM t2 LEFT JOIN t1 ON t2.id=t1.id WHERE t1.id is null;