找到重复的记录sql server

Question

我知道如何使用count（）查找重复值 但我的问题是如何找到重复的值，从一些字母开始，如＆＃39; A＆＃39;或者＆＃39; K＆＃39;

我有一个像这样的表格

id    rollnumber    city  fess
1   A100156       Ajamer 450
2   P102555       Pune   450
3   A100156       Ajamer 450
4   P102555       Pune   450

查询

select rollnumber,count(rollnumber) AS COUNTOF
from tblmytable
group by rollnumber
having count(rollnumber) > 1
order by rollnumber

给了我这个结果

rollnumber countof
    A100156       2
    P102555       2

我想找到以＆＃39; A＆＃39;

开头的重复卷号

像这样如何修改查询

Answer 1

只需在

上加上WHERE子句

select rollnumber,count(rollnumber) AS COUNTOF
from tblmytable
where rollnumber like 'A%'
group by rollnumber
having count(rollnumber)>1 order by rollnumber