Question

我有一个查询在这里我得到一个错误，别名说未知列，这是错误的。我需要得到16_judge_61,16_judge_62,16_judge_63

的总和

SELECT s.contestant_number, c.contestant_name, j.judge_name, 

SUM(CASE WHEN s.crit_id =17 AND s.judge_id =  '61' THEN score END ) AS 16_judge_61, 
SUM(CASE WHEN s.crit_id =17 AND s.judge_id =  '62' THEN score END ) AS 16_judge_62,
SUM(CASE WHEN s.crit_id =17 AND s.judge_id =  '63' THEN score END ) AS 16_judge_63,

(16_judge_61 + 16_judge_62 + 16_judge_63) as total //<--here is the problem
 //<--i also tried (sum(16_judge_61) + sum(16_judge_62) + sum(16_judge_63))as total not working as well


FROM tbl_score s INNER JOIN tbl_contestant c ON s.contestant_number = c.contestant_number
INNER JOIN tbl_judges j ON j.judge_id = s.judge_id
WHERE c.gender =  'male'
AND c.con_id = s.con_id
AND j.judge_id =62
GROUP BY s.contestant_number

Answer 1

您的错误是由于尝试在定义它的同一SELECT子句中使用别名而引起的。你不能这样做，因为尚未计算别名。

对此问题的膝跳反应只是将CASE，16_judge_61和16_judge_62的三个16_judge_63语句加在一起。但是，您可以通过识别使用CASE对三个WHERE IN值将这三个条件合并为一个judge_id语句来改进这一点。

尝试此查询：

SELECT s.contestant_number,
       c.contestant_name,
       j.judge_name,
       SUM(CASE WHEN s.crit_id = 17 AND s.judge_id IN (61,62,63)
                THEN score END ) AS total
FROM ...

Answer 2

不确定您使用SUM（CASE ...）

的原因

SELECT s.contestant_number, c.contestant_name, j.judge_name, 

    CASE WHEN s.crit_id =17 AND s.judge_id =  '61' THEN score END  AS 16_judge_61, 
    CASE WHEN s.crit_id =17 AND s.judge_id =  '62' THEN score END  AS 16_judge_62,
    CASE WHEN s.crit_id =17 AND s.judge_id =  '63' THEN score END  AS 16_judge_63,

    SUM(16_judge_61 + 16_judge_62 + 16_judge_63) as total 


    FROM tbl_score s INNER JOIN tbl_contestant c ON s.contestant_number = c.contestant_number
    INNER JOIN tbl_judges j ON j.judge_id = s.judge_id
    WHERE c.gender =  'male'
    AND c.con_id = s.con_id
    AND j.judge_id =62
    GROUP BY s.contestant_number

Answer 3

您可以使用子查询，如下所示：

SELECT *, (16_judge_61+16_judge_62+16_judge_63) AS total FROM (

-------------Your wholequery----------------

) t

MySQL：如何按别名的名称获取sum列

3 个答案: