mysql - MySQL - 用 COUNT 更新，可能吗？

Question

如果“name”和“address_1”有重复条目，我正在尝试更新 MySQL 表以将“已处理”列名显示为“2”，但它不起作用 - 像往常一样，我想我只是有点一个白痴的..

这就是我正在尝试的

UPDATE `records`
SET `processed`='2', `count` = (SELECT COUNT(`user`)
FROM `records`
WHERE `name`<>''
AND `address_1`<>'')
WHERE `count`=> '1';

基本上，如果有多个“名称”和“地址_1”，则“已处理”字段需要更新为“2”。

Answer 1

您可以使用这样的查询来返回重复的名称和地址：

SELECT name, address_1, COUNT(*) cnt
FROM records
GROUP BY name, address_1
HAVING COUNT(*)>1

然后将此查询连接到记录表，并将处理的列更新为连接成功的 2：

UPDATE
  records INNER JOIN (SELECT name, address_1, COUNT(*) cnt
                      FROM records
                      GROUP BY name, address_1
                      HAVING COUNT(*)>1) duplicates
  ON records.name = duplicates.name
     AND records.address_1=duplicates.address_1
SET
  `processed`='2',
  `count` = duplicates.cnt
WHERE 
  records.`name`<>''
  AND records.`address_1`<>''