Question

我有一个名为sample的表，它有3列。

id   customer   default_address

1     1         0   
2     1                 0

3     1         0   
4     1         0   
5     2         0   
6     2         0   
7     3         0   
8     3         0   
9     2         0

10    2         0

这里我想按客户分组并更新第一个默认地址应为1，并为每个客户全部为0。怎么做mysql查询？感谢

Answer 1

UPDATE  tb a
        LEFT JOIN
        (
            SELECT  customer, MIN(id) id
            FROM    tb
            GROUP   BY customer
        ) b ON a.customer = b.customer AND
                a.ID = b.ID
SET     a.default_address = b.ID IS NOT NULL

SQLFiddle Demo

Answer 2

UPDATE sample 
  LEFT JOIN 
  (SELECT MIN(id) id,customer 
   FROM sample 
   GROUP BY customer) t ON sample.customer=t.customer 
SET default_address="1" 
WHERE sample.id=t.id;

这应该有用。

Answer 3

Update Table1 
INNER JOIN (Select Min(`id`) as MinID,`customer`
From Table1 Group by `customer`) t2
SET Table1.`default_address` = 1
WHERE Table1.`id` = t2.MinID;

<强> SAMPLE FIDDLE

示例表的Mysql Update Query

3 个答案: