我想在MySQL数据库中取出重复的记录。这可以用:
SELECT address, count(id) as cnt FROM list
GROUP BY address HAVING cnt > 1
结果是:
100 MAIN ST 2
我想要拖动它，以便它显示复制的每一行。喜欢的东西:
JIM JONES 100 MAIN ST
JOHN SMITH 100 MAIN ST
有什么想法可以做到吗?我试图避免做第一个，然后在代码中用第二个查询查找重复。
当前回答
会是这样的:
SELECT t1.firstname t1.lastname t1.address FROM list t1
INNER JOIN list t2
WHERE
t1.id < t2.id AND
t1.address = t2.address;
其他回答
select `cityname` from `codcities` group by `cityname` having count(*)>=2
这是你问的类似的问题，它是200%的工作和简单。 享受! !
SELECT id, count(*) as c
FROM 'list'
GROUP BY id HAVING c > 1
这将返回id和该id重复的次数，或者什么都没有，在这种情况下，您将不会有重复的id。
通过(例如:address)更改组中的id，它将返回一个地址由第一个找到的id与该地址重复标识的次数。
SELECT id, count(*) as c
FROM 'list'
GROUP BY address HAVING c > 1
我希望这能有所帮助。喜欢。)
这还将显示有多少重复项，并将在没有连接的情况下对结果进行排序
SELECT `Language` , id, COUNT( id ) AS how_many
FROM `languages`
GROUP BY `Language`
HAVING how_many >=2
ORDER BY how_many DESC
我们也可以发现重复依赖于不止一个字段。对于这些情况，您可以使用下面的格式。
SELECT COUNT(*), column1, column2
FROM tablename
GROUP BY column1, column2
HAVING COUNT(*)>1;
SELECT *
FROM (SELECT address, COUNT(id) AS cnt
FROM list
GROUP BY address
HAVING ( COUNT(id) > 1 ))
