mysql - 子组外的引用字段(where 子句中的未知列)

Question

我试图在子查询内引用a.pointer，但看起来mysql不允许引用子查询外部的字段。

UPDATE order_items AS a

SET a.id_parent = (

SELECT id FROM((

select id from order_items as b where (b.pointer = a.pointer) and (b.id_parent = 0)) 

)x) 

WHERE a.id_parent > 9999

访问子查询内的 a.pointer 的最佳方式是什么？

Answer 1

看起来您正尝试在此处进行自连接；类似的东西

UPDATE order_items a 
    JOIN order_items b ON b.pointer = a.pointer AND b.id_parent = 0
SET a.id_parent = b.id
WHERE a.id_parent > 9999;