mysql子查詢錯誤[21000] [1241]操作數應包含1列

Question

我有一張桌子叫做交易對手。 我將在此表上進行查詢，如下所示：

SELECT (`name`, `mark`, `parent`, `description`) AS table_1 FROM (SELECT 
`name`, `mark`, `parent`, `description` FROM counterparty) AS table_2 WHERE 
(table_1.mark <> table_2.parent);

但是下面的錯誤顯示：

[21000] [1241]操作數應包含1列

我該如何解決？

Answer 1

您可以在下面嘗試-使用SELF JOIN

SELECT table_1 .`name`, table_1.`mark`, table_1.`parent`, table_1 .`description` 
FROM counterparty table_1 inner join counterparty table_2 
table_1.mark <> table_2.parent;

Answer 2

您編寫子查詢錯了，可以通過使用join嘗試如下

SELECT  t1.* from table_1 t1    
 join  (SELECT 
`name`, `mark`, `parent`, `description` FROM counterparty
       ) AS table_2 t2 on  t1.mark!=t2.mark