Question

SELECT a.id, a.name, a.ad, c.name, c.phone, c.email,
    (
        SELECT b.id_user
        FROM price_b b
        WHERE b.id = a.id
        ORDER BY b.date DESC
        LIMIT 1
    ) AS f_user_id
    FROM a_emtp a
    LEFT JOIN customer c ON
    c.id = f_user_id
    WHERE a.show = "1"

嗨，为什么要显示此错误：'on clause'

中的未知列'f_user_id'

由于

Answer 1

SELECT a.id, a.name, a.ad, c.name, c.phone, c.email,
(
    SELECT b.id_user
    as f_user_id
    FROM price_b b
    WHERE b.id = a.id
    ORDER BY b.date DESC
    LIMIT 1
)
FROM a_emtp a
LEFT JOIN customer c ON
c.id = f_user_id
WHERE a.show = "1"

您可以引用外部查询中子查询中的带标签字段。您甚至可以删除重新标记，只需使用“b.id_user”。

Answer 2

可能是c.email丢失后的逗号。

SELECT a.id, a.name, a.ad, c.name, c.phone, c.email,
(
    SELECT b.id_user
    FROM price_b b
    WHERE b.id = a.id
    ORDER BY b.date DESC
    LIMIT 1
) AS f_user_id
FROM a_emtp a
LEFT JOIN customer c ON
c.id = f_user_id
WHERE a.show = "1"

mysql，使用两个select和order by，new value

2 个答案: