sql语句怎么查重
2023-05-08 00:23:17
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问:SQL查询语句,怎样查询重复数据
- 答:select count(*),id from 表名 group by id having count(*)>1
- 答:我们假如在goods表中id是唯一的,其中name可能会相同,现在要查出name存在重复的所有条目,sql可以这样写,可能理解不同,仅供参考
select id,name from goods WHERE name in ( SELECT name FROM goods GROUP BY name HAVING COUNT(name) > 1) - 答:是要把重复的ID查出来嘛?
select id
from A
group by id
Having count(id)>1 - 答:select id, name, memo
from A
where id in (select id from A group by id having count(1) >= 2) - 答:select id,count(1) 重复次数 from A group by id having count(1)>1;
查询出来的结果都是id重复的,重复次数 中的数值就是重复了多少次。 - 答:select id,count(*) from A group by A.id havinig count(*)>1;
- 答:1、第一步,打开数据库,并创建一个包含重复数据的新用户表,见下图,转到下面的步骤。
2、第二步,执行完上面的操作之后,输入如下红框中的SQL语句,然后单击运行按钮,以查看数据库中用户表中的重复数据,见下图,转到下面的步骤。
3、第三步,执行完上面的操作之后,查找出了具有重复名称的数据,见下图,转到下面的步骤。
4、第四步,执行完上面的操作之后,可以使用如下语句来去除重复数据,见下图,转到下面的步骤。
5、第五步,执行完上面的操作之后,最终删除了同一类中的重复数据,见下图。这样,就解决了这个问题了。
- 答:查询重复数据,方法如下:
select * from [表A] where id in (select id from [表A] group by id having count(id) >1 ) - 答:select id, name, memo from A where id in (select id from A group by id having count(1) >= 2)
- 答:selectid,name,memo
fromA
whereidin(selectidfromAgroupbyidhavingcount(1)>=2)
1查询 abcd相同的记录:
select * from F where a=b and b=c and c=d
2查询有重复数据的记录
select * from F group by a,b,c,d having count(*)>1
3取出数据过滤到重复的数据
select distinct a,b,c,d from f - 答:select id,count(1) as num from table where num>1 group by id
问:怎么用SQL语句查数据库中某一列是否有重复项
- 答:SELECT
某一列,
COUNT( 某一列 )
FROM
表
GROUP BY
某一列
HAVING
COUNT( 某一列 ) 〉1
这样查询出来的结果, 就是 有重复, 而且 重复的数量。 - 答:我的想法是比较count(列)和count(distinct 列)是否相等。不知道大家有没有更好的方法。
问:SQL语句怎么查重复数据?
- 答:select count(字段) from table
select count(distinct 字段) from table
不相等就说明有重复字段了
然后再查重复值
select count(字段) as total,字段 from table where total > 1 group by 字段 - 答:如下面的语句可以查询 empID(员工工号) 重复(大于 1 次)的纪录
select empID, count(*) from employee group by empID having count(*) > 1;
还可以用下面的语句查询重复员工的详细记录
select * from employee where empid in (select empID from employee group by empID having count(*) > 1) ; - 答:可以通过count来统计。
问:使用sql server 怎么查重复数据
- 答:1、最直观的思路:要知道所有名字有重复人资料,首先必须知道哪个名字重复了:
select name from emp group by name having count(*)>1
所有名字重复人的记录是:
select * from emp
where name in (select name from emp group by name having count(*)>1)
2、稍微再聪明一点,就会想到,如果对每个名字都和原表进行比较,大于2个人名字与这条记录相同的就是合格的 ,就有:
select * from emp
where (select count(*) from emp e where e.name=emp.name) >1 - 答:SELECT *,
count(*) C
FROM 表明
GROUP BY 字段
ORDER C DESC
问:sql查询按两个字段查询重复记录
- 答:应该是in关键字不支持多字段吧,你这样试一下
select *
from shiyan003 a
where exists (select 1
from (select xm, sfzhm
from shiyan003
group by xm, sfzhm
having count(*) > 1) s
where s.xm = a.xm
and s.sfzhm = a.sfzhm) - 答:select *
from shiyan003 a
where exists (select 1
from (select xm, sfzhm
from shiyan003
group by xm, sfzhm
having count(*) > 1) s
where s.xm = a.xm
and s.sfzhm = a.sfzhm) - 答:select * from 表 a where a.a1=条件1 and a.a2=条件2
group by 所有的列
祝楼主好运 - 答:select * from shiyan003 a
where a.xm in (select xm from shiyan003 group by xm,sfzhm having count(*) > 1)
and a.sfzhm in (select sfzhm from shiyan003 group by xm,sfzhm having count(*) > 1)
原句的错在in的使用上 - 答:这样肯定有错的你看看IN (SELECT XM FROM SHIYAN003)一个IN只能一个字段。
SELECT COUNT(1) FROM SHIYAN003 A GROUP BY A.XM,A.SFZHM HAVING COUNT(1) > 1
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