我有以下查询：

SELECT DISTINCT(uniq)
FROM
(
    SELECT sex AS uniq FROM type4
    UNION
    SELECT fason AS uniq FROM type4
    UNION
    SELECT color AS uniq FROM type4
    UNION
    SELECT size AS uniq FROM type4
) AS Temp

它运作得很好,它返回：

[uniq] => some unique value

是否可以知道此唯一值来自哪个列？
我的意思是这样的：

[uniq] => some unique value
[from] => size

我怎样才能做到这一点？

解决方法:

SELECT DISTINCT(uniq)
FROM
(
    SELECT (sex + ' 1') AS uniq FROM type4
    UNION
    SELECT (fason + ' 2') AS uniq FROM type4
    UNION
    SELECT (color + ' 3') AS uniq FROM type4
    UNION
    SELECT (size + ' 4') AS uniq FROM type4
) AS Temp

然后你可以使用substring从右边删除最后2