计算每一行

Question

这个查询有什么问题？

SELECT *, (SELECT COUNT(*)
FROM
(
    SELECT NULL
    FROM words
    WHERE project=projects.id
    GROUP BY word
    HAVING COUNT(*) > 1
) T1) FROM projects

MySQL在'where子句'中返回1054 Unknown列'projects.id'

谢谢

Answer 1

这有用吗？

SELECT *, (SELECT COUNT(*)
    FROM words
    WHERE words.project=projects.id) as pCount
 FROM projects