无法修复mysql查询中的语法错误

Question

这个查询中的语法错误是什么？我无法修复。

SELECT 
    wsd.sid,
    wsd.data as node_id
FROM 
    webform_submitted_data wsd
    JOIN (
        SELECT 
            wsd.sid, 
            wsd.data as md_email
        FROM 
            webform_submitted_data wsd
        WHERE
            wsd.nid=48 AND wsd.cid=5
    ) tbl_md_email tmm ON tmm.sid = wsd.sid 
WHERE
    wsd.nid=48 AND wsd.cid=4

Answer 1

试试这个：

SELECT 
    wsd.sid,
    wsd.data AS node_id
FROM 
    webform_submitted_data AS wsd
    JOIN 
    (
        SELECT 
            sid, 
            data AS md_email
        FROM 
            webform_submitted_data
        WHERE
            nid=48 AND cid=5
    ) AS tmm ON tmm.sid = wsd.sid 
WHERE
wsd.nid=48 AND wsd.cid=4;

Answer 2

可能是因为您在两个select中使用了相同的别名："webform_submitted_data wsd“

尝试更改别名："webform_submitted_data wsd1“和"webform_submitted_data wsd2”(用于内部选择)

SP.