sql - SQL 过滤器不能在语句中使用别名

Question

尝试执行我的语句时，我不断收到错误，说如下：

ERROR [42703] [IBM][DB2/LINUXX8664] SQL0206N "HAO" is not valid in the context where it is used.

错误指的是我的过滤器，因为它在注释掉时可以正常工作。见下文：

SELECT
    ROUND(MINUTESDIFF(CURRENT_DATE,LAST_ACTION_DATE)/60,2) AS HAO
FROM [database]
WHERE   1=1
    AND QTY     >      0
    AND STATE   =      'Active'
    AND HAO     >      5

ORDER BY ONHOLD DESC

你不能使用像“HAO”这样的别名作为过滤器吗？我想我以前看过它，所以我一定做错了什么，请告诉我，谢谢！

Answer 1

您不能在 DB2 中同时创建和使用字段（其他数据库确实允许这样做）。

你应该这样做：

SELECT HAO
FROM (
    SELECT
        ROUND(MINUTESDIFF(CURRENT_DATE,LAST_ACTION_DATE)/60,2) AS HAO,
        ONHOLD
    FROM [database]
    WHERE   1=1
        AND QTY     >      0
        AND STATE   =      'Active'
) TMP 
WHERE HAO     >      5
ORDER BY ONHOLD DESC

或者：

SELECT
    ROUND(MINUTESDIFF(CURRENT_DATE,LAST_ACTION_DATE)/60,2) AS HAO
FROM [database]
WHERE   1=1
    AND QTY     >      0
    AND STATE   =      'Active'
    AND ROUND(MINUTESDIFF(CURRENT_DATE,LAST_ACTION_DATE)/60,2) > 5
ORDER BY ONHOLD DESC