mysql - 选择子查询的结果

Question

我正在尝试选择 q1.res，这将是 FROM 子查询的结果:

    (SELECT SUM(gwr.res1)/(COUNT(*)*1000) as 'res' 
     FROM process.gwr 
     WHERE started = 1 AND gwr.user2 = g.id AND gwr.loss = g.id) AS q1

问题是我试图在子查询中选择g.id，但由于某种原因它无法访问它并返回错误消息:

[Err] 1054 - “where 子句”中存在未知列“g.id”

这没有意义，因为 g.id(grand.id 具有 id 列)

SELECT
    g.name, g.point, g.mx, q1.res
FROM
    (SELECT SUM(gwr.res1)/(COUNT(*)*1000) as 'res' 
     FROM process.gwr 
     WHERE (started = 1) AND (gwr.user2 = g.id) AND (gwr.loss = g.id)) AS q1, grand g
LEFT JOIN process.users p ON (p.id = g.owner)
WHERE
    p.name != ""
ORDER BY
    g.point DESC,
    g.mx DESC
LIMIT 5

问题出在哪里？

Answer 1

尝试从子查询的“res”中删除“”。

SELECT
    g.name, g.point, g.mx, q1.res
FROM
    (SELECT SUM(gwr.res1)/(COUNT(*)*1000) as res FROM process.gwr WHERE started = 1 AND gwr.user2 = g.id AND gwr.loss = g.id) AS q1, grand g
LEFT JOIN process.users p ON (p.id = g.owner)
WHERE
    p.name != ""
ORDER BY
    g.point DESC,
    g.mx DESC
LIMIT 5