sql - ORA-00904 无效标识符错误

Question

我得到 ORA-00904 'c' 无效标识符错误。这个别名有什么问题？

select NO, count(JOINT_NO) as c
from JOINT
WHERE HOLDER = 'Y' AND JOINT.c > 1
GROUP BY NO;

Answer 1

我想你想获取那些计数 > 1 的记录。所以你不能Indentifier C在同一个查询的WHERE子句中使用。

select NO, count(JOINT_NO) as c
from JOINT
WHERE HOLDER = 'Y'
GROUP BY NO
HAVING COUNT(JOINT_NO)>1;

Answer 2

ctable 中不存在列JOINT，导致您收到错误消息。

像这样更改您的查询：

select NO, count(JOINT_NO) as c
from JOINT
WHERE HOLDER = 'Y'
GROUP BY NO
HAVING count(JOINT_NO) > 1;

Answer 3

您可以在 FROM 子句中使用子选择（子查询）：

 select T1.NO,T1.c
    from
    (
      select NO, count(JOINT_NO) as c
      from JOINT
      WHERE HOLDER = 'Y' 
      GROUP BY NO
    ) as T1
    where T1.c > 1

你也可以使用有：

    select NO, count(JOINT_NO) as c
    from JOINT
    WHERE HOLDER = 'Y'
    GROUP BY NO
    HAVING COUNT(JOINT_NO)>1