数据库 - 关于原生mysql语句多表查询更新字段问题 求大神解答

Question

a.user_id	a.school_id
1233	22013
2346	22017
2344	23445
2247	22017
...	...

b.user_id	b.term
2346	1
2346	1
2346	2
2347	2
1233	1
...	...

如上两张表，根据a.school_id=22017得到它的user_id然后根据此user_id得到 b.term，并把term=1的变为term=2，把term=2的变为term=1

Answer 1

UPDATE b LEFT JOIN a ON a.user_id = b.user_id SET b.term = IF(b.term!=1,1,2) WHERE a.school_id = '22017'