我有一个varchar列的表，我想找到在这个列中有重复值的所有记录。我可以使用什么查询来查找重复项?
当前回答
如果你想删除重复使用DISTINCT
否则使用这个查询:
SELECT users.*，COUNT(user_ID) as user FROM users GROUP BY user_name有用户>
其他回答
对GROUP BY子句执行SELECT操作。假设name是你想要在其中找到重复项的列:
SELECT name, COUNT(*) c FROM table GROUP BY name HAVING c > 1;
这将返回一个在第一列中包含名称值的结果，以及该值在第二列中出现次数的计数。
SELECT
t.*,
(SELECT COUNT(*) FROM city AS tt WHERE tt.name=t.name) AS count
FROM `city` AS t
WHERE
(SELECT count(*) FROM city AS tt WHERE tt.name=t.name) > 1 ORDER BY count DESC
如果你想删除重复使用DISTINCT
否则使用这个查询:
SELECT users.*，COUNT(user_ID) as user FROM users GROUP BY user_name有用户>
Select column_name, column_name1,column_name2, count(1) as temp from table_name group by column_name having temp > 1
SELECT t.*,(select count(*) from city as tt
where tt.name=t.name) as count
FROM `city` as t
where (
select count(*) from city as tt
where tt.name=t.name
) > 1 order by count desc
用你的表格替换城市。 将name替换为字段名
