Redundant duplicate records in SQL Server lookup table

1, look for redundant records in the table, duplicate records are based on a single field (Peopleid) to determine
Select
* FROM people
where Peopleid in (selectPeopleidFrom
PeopleGroupByPeopleidHavingCount (Peopleid)
> 1)

2, delete redundant records in the table, duplicate records are based on a single field (Peopleid) to judge, leaving only the smallest ROWID records
Delete
from people
where PeopleidIn (selectPeopleidFrom
PeopleGroupByPeopleidHaving
Count (Peopleid) > 1)
and rowID not in (select min (rowid) from
PeopleGROUP BY PeopleidHaving count (Peopleid
) >1)

3. Find redundant duplicate records (multiple fields) in the table
SELECT * FROM Vitae a
Where (A.PEOPLEID,A.SEQ)
In (select Peopleid,seq to Vitae GROUP by Peopleid,seq have
COUNT (*) > 1)

4. Delete extra duplicate records (multiple fields) in the table, leaving only the record with ROWID minimum
Delete from Vitae a
where
(A.PEOPLEID,A.SEQ) in (select Peopleid,seq from Vitae GROUP by
Peopleid,seq having Count (*) > 1)
and rowID not in (select min (rowid) from
Vitae GROUP BY PEOPLEID,SEQ have Count (*) >1)

5. Find redundant duplicate records (multiple fields) in the table, not including the smallest ROWID records
SELECT * FROM Vitae a
where
(A.PEOPLEID,A.SEQ) in (select Peopleid,seq from Vitae GROUP by
Peopleid,seq having Count (*) > 1)
and rowID not in (select min (rowid) from
Vitae GROUP BY PEOPLEID,SEQ have Count (*) >1)

Two
Say
A field "name" exists in table A,
and the "name" value may be the same between different records,
Now is the need to query out the records in the table, "name" value has duplicate entries;
Select
Name,count (*) from A Group by Name have Count (*) > 1

If you also look at the same gender, the following is true:
Select Name,sex,count (*) from A Group by Name,sex have
Count (*) > 1

Source: http://www.cnblogs.com/tiasys/archive/2012/09/22/2697728.html

From for notes (Wiz)

Redundant duplicate records in SQL Server lookup table