ERROR 1241 (21000): 执行查询时操作数应包含 1 列答案

【问题标题】：ERROR 1241 (21000): Operand should contain 1 column(s) when executing queryERROR 1241 (21000): 执行查询时操作数应包含 1 列
【发布时间】：2012-11-25 06:37:03
【问题描述】：


INSERT INTO People(Track_id_Reference) 
SELECT track_id 
FROM Tracks 
WHERE track_title IN (SELECT tracktitle 
                      FROM top100 
                      WHERE artist IN (SELECT p.People_name, t.artist 
                                       FROM People AS p 
                                       RIGHT JOIN top100 AS t 
                                       ON 
                                       p.People_name=t.artist 
                                       UNION DISTINCT 
                                       SELECT p.People_name, t.artist 
                                       FROM People AS p 
                                       LEFT JOIN top100 AS t 
                                       ON 
                                       p.People_name=t.artist));

我得到的错误是

ERROR 1241 (21000): Operand should contain 1 column(s)

联合返回 2 列的子查询。我该如何解决这个问题？

【问题讨论】：

很明显，您可以通过只选择一列而不是两列来解决此问题。
你能解释清楚吗我没看懂

标签： mysql sql mysql-error-1241

【解决方案1】：

你缺少FROM子句

SELECT track_id 
FROM   tableName
WHERE track_title

所以完整的查询应该是

INSERT INTO People (Track_id_Reference)
SELECT track_id
FROM                                      -- <<== add tableName here
WHERE track_title = (
                SELECT tracktitle
                FROM top100
                WHERE artist = (
                                SELECT p.People_name,
                                        t.artist
                                FROM People AS p
                                RIGHT JOIN top100 AS t
                                        ON p.People_name = t.artist

                                UNION

                                        DISTINCT
                                SELECT p.People_name,
                                        t.artist
                                FROM People AS p
                                LEFT JOIN top100 AS t
                                        ON p.People_name = t.artist
                                )
                );

另一个很快会出现的问题是在子查询的结果上使用等号=，使用IN比使用=更安全，因为它会抛出一个例外，例如，子查询将返回多个值。例如，

INSERT INTO People (Track_id_Reference)
SELECT track_id
FROM                                      -- <<== add tableName here
WHERE track_title IN (
                SELECT tracktitle
                FROM top100 .............

【讨论】：

@Xymotech：你不会因为慢而获得 41k 代表。 :)
感谢您的快速回复，我已编辑并发布了一个新错误，请您帮忙
使用IN子句时，子查询的结果应该只有一列，例如WHERE artist IN ( SELECT t.artist FROM People