如何计算别名列上的聚合函数SUM?如何计算别名列上的聚合函数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
你可以使用子查询。祝你好运! – Kermit
SUM(COUNT(a.step_id))总数。别名仅适用于GROUP BY,ORDER BY或HAVING(除直接输出外)。 –
请给我例子..;) – afriex