mysql查询某个字段中是否有重复的值

借鉴博客:https://www.cnblogs.com/loveufofbi/p/12148988.html

方法一

SELECT *
FROM (

SELECT `openid` , COUNT( * ) AS c
FROM ing_jf_shop
GROUP BY `openid`
)t
WHERE c >1

方法二

SELECT openid ,
        COUNT(openid)
FROM  ing_jf_shop
GROUP BY openid
HAVING  COUNT(openid) > 1

-- ing_jf_shop 是表名

-- openid 是要确定是否有重复值的字段

原文地址:https://www.cnblogs.com/spll/p/13355843.html