Mysql 用同一表中的另一行值更新一行

问题描述

我有一张桌子.我想用同一个表中的第 10 行值更新第 5 行.例如:

I have a table. I want to update the 5th row with 10th row values from the same table. For example:

SlNo   Name Quali   Exp
1        x   B.E     2
2        y   BSC     3
3        Z   B.A     1.5
4        A   MSC     2
5        B   MBA     5

这里我想用第 5 行的值更新第二行.

Here i want to update second row with the value of 5th row.

这是我当前的查询:

    UPDATE table 
      SET Name=(select Name from table where slNo='5'),
               Quali=(select Quali from  table where slNo='5'),
               Exp=(select Exp from table where slNo='5') 
      where slNo='3';

这工作正常......但是如果有超过 20 列，以这种方式编写查询会变得很费力，因为对于每一列，我必须包含另一个子查询......还有其他方法可以编写吗?查询以使用同一表中另一行的所有值更新整行?

this is working fine ... but if there are more than 20 columns it becomes laborious to write a query this way, because for each column I have to include another sub-query... is there any other way to write query to update the whole row with all values from the other row in the same table?

推荐答案

使用多表的自联接 UPDATE 语法:

Use a self-join with the multiple table UPDATE syntax:

UPDATE `table` AS t1 JOIN `table` AS t2 ON t2.slNo = 5
SET    t1.Name = t2.Name, t1.Quali = t2.Quali, t1.Exp = t2.Exp
WHERE  t1.slNo = 3

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