Sunday 1 November 2015

How to delete duplicate row in Sql Server?



How to delete duplicate row in Sql Server?

Here i use only name column

select * from student1 order by name,age

id          name                  age
----------- --------------------- -----------
7           Ramu Kumar            30
14          Sachi Supriya         25
18          Sachi                 28
19          Ramu                  29
20          ramu                  30
22          ramu                  29

insert into student1(name,age) values('ramu',29)

id          name                     age
----------- ------------------------ -----------
19          Ramu                     29
22          ramu                     29
23          ramu                     29
20          ramu                     30
7           Ramu Kumar               30
18          Sachi                    28
14          Sachi Supriya            25

WITH tblDuplicate as
(
SELECT ROW_NUMBER() Over(PARTITION BY Name ORDER BY Name)
   As RowNumber,* FROM student1
)
SELECT * FROM tblDuplicate

RowNumber  id      name                age
-------   ------- ----------- ------ --------
1         19      Ramu                 29
2         20      ramu                 30
3         22      ramu                 29
4         23      ramu                  29
1         7       Ramu Kumar            30
1         18      Sachi                 28
1         14      Sachi Supriya         25

WITH tblDuplicate as
(
SELECT ROW_NUMBER() Over(PARTITION BY Name ORDER BY Name)
   As RowNumber,* FROM student1
)
DELETE FROM tblDuplicate where RowNumber >1

(3 row(s) affected). its mean deleted
Now No duplicate row found ...
WITH tblDuplicate as
(
SELECT ROW_NUMBER() Over(PARTITION BY Name ORDER BY Name)
   As RowNumber,* FROM student1
)
SELECT * FROM tblDuplicate

RowNumber       id       name            age
------------- ------ -------------------------
1             19         Ramu            29
1             7          Ramu Kumar      30
1             18         Sachi           28

1             14         Sachi Supriya   25

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