使用count子查询后插入MYSQL
我试图将一些数据插入表中,但仅当子查询计数>0时 这就是我目前所拥有的使用count子查询后插入MYSQL,mysql,insert,subquery,nested-queries,Mysql,Insert,Subquery,Nested Queries,我试图将一些数据插入表中,但仅当子查询计数>0时 这就是我目前所拥有的 INSERT INTO users_friends (userId, friendId) VALUES (77, 100) WHERE (SELECT COUNT(id) FROM users WHERE email = 'a@g.com') > 0 仅供参考,这两个查询都独立工作 这应该是一个简单的修复。干杯 另一种方法是: INSERT INTO users_friends (userId, friendI
INSERT INTO users_friends (userId, friendId) VALUES (77, 100)
WHERE
(SELECT COUNT(id) FROM users WHERE email = 'a@g.com') > 0
仅供参考,这两个查询都独立工作
这应该是一个简单的修复。干杯
另一种方法是:
INSERT INTO users_friends (userId, friendId)
SELECT 77, 100
FROM dual
WHERE EXISTS
( SELECT * FROM users WHERE email = 'a@g.com' ) ;
试试这个:
INSERT INTO users_friends (userId, friendId)
(SELECT 77, 100 FROM users GROUP BY email HAVING email= 'a@g.com' and count(id)>0)
但在本例中,若count-example=4,则将向表中插入4条记录(77100),这是一种非常棒的方法!干杯
INSERT INTO users_friends (userId, friendId)
(SELECT 77, 100 FROM users GROUP BY email HAVING email= 'a@g.com' and count(id)>0)
INSERT INTO users_friends (userId, friendId)
SELECT 77, 100 FROM users WHERE email = 'a@g.com'
GROUP BY email
HAVING COUNT(id) > 0