Question

我不知道为什么这段代码不起作用。引发语法错误，但据我所知，这应该有效。有人可以向我解释我做错了什么。

insert into playerteam(playerId, teamId) select id from player where 
  player.firstname='John' and select id from team where team.`name`='Swim Team';

Answer 1

使用如下：

INSERT INTO playerteam(playerId, teamId) 
SELECT (SELECT id FROM player WHERE player.firstname='John'), 
    (SELECT id FROM team WHERE team.`name`='Swim Team');

Answer 2

此：

player.firstname='John' and select id from team where team.`name`='Swim  Team';
                     ^^^^^^^^^

您不能只将整个查询结果作为where子句返回。你必须以某种方式测试结果，例如

... AND EXISTS select ...
         ^^^^

Answer 3

您的select查询不正确 - 您无法使用select ... AND select ...合并两个查询，您需要使用join

例如（但是你需要在这里添加连接的ON部分，以便连接两个表）：

insert into playerteam(playerId, teamId) select player.id as playerId, 
  team.id as teamId from player inner join team on {ADD HERE COLUMNS TO JOIN BY}
where player.firstname='John' and  team.`name`='Swim Team';

SQL关联实体

3 个答案: