mysql - MySQL对表的每一行重复操作

Question

我想为另一个表中存在的所有值更新 MySQL 中列的值，但是当我尝试执行此操作时，出现以下错误。我怎样才能做到这一点？

 update table1 set value = "0" where url = (select * from url_list) ; 
 ERROR 1242 (21000): Subquery returns more than 1 row

有什么想法吗？

score 2 · Accepted Answer

您可以将“IN”用于“=”运算符或

(select * from url_list)

查询应该只返回一行。

score 1 · Accepted Answer

假设如果 url 存在于 url_list 的 url 列中，则将值设置为 0，请尝试

update table1 set value = "0" where url in (select url from url_list);

score 0 · Accepted Answer

如果您将其更改=为IN：

update table1 set value = "0" where url IN (select * from url_list);

score 0 · Accepted Answer

0

update table1 set value = "0" where url IN (select * from url_list)

于 2013-01-14T17:17:01.917 回答

score 0 · Accepted Answer

0

更改查询的结尾：

WHERE url IN (select url from url_list)

于 2013-01-14T17:17:14.490 回答

score 0 · Accepted Answer

0

UPDATE table1 x
  JOIN url_list y
    ON y.url = x.url
   SET x.value = 0;

于 2013-01-14T17:27:03.990 回答

6 回答 6