Question

我正在尝试进行查询，我想在此表中插入一些具有指定条件的选择中的数据。

 INSERT INTO concediati (nume, prenume, idclient, idrent, idcar) 
 VALUES
     ((SELECT clients.Firstname FROM clients WHERE id = 1),
      (SELECT clients.lastname FROM clients WHERE id = 1), 
      (SELECT clients.id FROM clients WHERE idteam = 1), 
      (SELECT rentcar.id FROM rentcar WHERE idteam = 1), 
      (SELECT cars.id FROM cars WHERE idteam = 1) 
     );

此查询的问题是它引发了错误：

“子查询返回多个值。当子查询跟随=，<，<=，>或用作表达式时，不允许这样做。”

我尝试执行此交叉联接查询..但是它超越了我..我不知道该怎么做或该怎么做。

之所以这样做，是因为我想“解雇”一名员工，然后将所有数据发送到表或分配给另一名员工。

Answer 1

您可以JOIN 3张桌子。

INSERT INTO concediati (nume, prenume, idclient, idrent, idcar) 
SELECT c.FirstName, c.LastName, c.id, rc.id, ca.id
FROM clients c
JOIN rentcar rc ON rc.idteam = c.id
JOIN cars ca ON ca.idteam = c.id
WHERE c.id = 1

在JOIN

上添加条件

INSERT INTO concediati (nume, prenume, idclient, idrent, idcar) 
SELECT c.FirstName, c.LastName, c.id, rc.id, ca.id
FROM clients c
JOIN cars ca ON ca.idteam = c.id
JOIN rentcar rc ON rc.idteam = c.id AND rc.cardid = c.id
WHERE c.id = 1

Answer 2

假设每个子查询返回一条记录，则可以通过以下方式使用交叉联接：

insert into concediati (nume, prenume, idclient, idrent, idcar) 
select 
    c1.firstname,
    c1.lastname, 
    c2.id, 
    c3.id,
    c4.id
from 
    clients c1, 
    clients c2, 
    rentcar c3, 
    cars c4
where 
    c1.id = 1 and 
    c2.idteam = 1 and
    c3.idteam = 1 and 
    c4.idteam = 1

或者，使用联接：

insert into concediati (nume, prenume, idclient, idrent, idcar) 
select 
    c1.firstname,
    c1.lastname, 
    c2.id, 
    c3.id,
    c4.id
from 
    (
        (
            clients c1 inner join clients c2 on c1.id = c2.idteam
        )
        inner join rentcar c3 on c1.id = c3.idteam
    )
    inner join cars c4 on c1.id = c4.idteam
where 
    c1.id = 1

（由于未指定RDBMS，因此我假定要使用MS Access语法进行联接，因为在进行包围式处理时比较麻烦）。

SQL插入多个选择

2 个答案: