mysql - MYSQL WHERE 条件取决于 SELECT 列

Question

是否可以参考您在 WHERE 条件中选择的列？

我什至不知道如何在没有过多冗长的情况下提出这个问题，所以我将尝试将您指向“rated_user = @2User”部分并注意@2User 是我正在选择的。

SELECT id, user, minimum 
INTO @1ID, @1User, @minimum 
FROM table1 
WHERE a_or_b = 'a' AND item = itemName 
ORDER BY number DESC LIMIT 1;

SELECT id, user 
INTO @2ID, @2User 
FROM table1 
WHERE a_or_b = 'b' AND item = itemName 
    AND (SELECT IFNULL(AVG(rating),0) AS Rating 
            FROM table2 
            WHERE rated_user = @2User AND completed = 'y'
        ) >= @minimum_seller_rating 
ORDER BY number ASC LIMIT 1;

Answer 1

您也应该能够在子查询中使用父表中的原始列名。

WHERE rated_user = user 

如果存在名称冲突，您可能需要在其前面加上表名或别名。

WHERE rated_user = table1.user