如何在别名列上计算聚合函数 SUM?
SELECT a.question_id,
a.level,
Count(a.question_id) AS rank,
Sum(rank) AS total
FROM logs AS a,
question AS b
WHERE a.question_id = b.q_id
AND a.level = '2'
GROUP BY a.question_id
ORDER BY rank DESC
最佳答案
只需用 (SELECT alias) 包装您重复使用的别名:
SELECT a.question_id,
a.level,
COUNT(a.question_id) AS rank,
SUM(SELECT(rank)) AS total
FROM logs AS a,
question AS b
WHERE a.question_id = b.q_id
AND a.level = '2'
GROUP BY a.question_id
ORDER BY rank DESC
关于mysql - 如何计算别名列上的聚合函数 SUM?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/14217944/