Question

我有这个SQL查询：

SELECT date,
    CASE WHEN h_score > v_score
    THEN
        ho_t_id
    ELSE
        v_t_id
    END
FROM Games

我想在WHERE子句中使用所选的值（CASE WHEN语句）。我尝试做类似的事情：

SELECT date,
    CASE WHEN h_score > v_score
    THEN
        ho_t_id
    ELSE
        v_t_id
    END AS T
FROM Games
WHERE T = '1234'

这（当然）不起作用。

我该怎么做？

谢谢！

Answer 1

您可以在CTE中查询并将where子句放在一边。

with cte 
as
(
    SELECT date,
           CASE 
           WHEN h_score > v_score
           THEN ho_t_id
           ELSE v_t_id
           END AS T
    FROM Games
)
select * from cte where T = '1234

Answer 2

SELECT date, T FROM (
    SELECT date,
        CASE WHEN h_score > v_score
        THEN
            ho_t_id
        ELSE
            v_t_id
        END AS T
    FROM Games
) g
WHERE g.T = '1234'

Answer 3

只需在CASE子句中重复WHERE：

SELECT date,
    CASE WHEN h_score > v_score
    THEN
        ho_t_id
    ELSE
        v_t_id
    END AS T
FROM Games
WHERE (CASE WHEN h_score > v_score
    THEN
        ho_t_id
    ELSE
        v_t_id
    END) = '1234'

在WHERE子句中使用CASE WHEN的Selected值

3 个答案: