Write a query to delete duplicate records in SQL SERVER
Answer Posted / inder kumar singh
1) If all coumns are duplicate
create tablet tbl_deleteDuplicate
(
emp_id numeric,emp_name varchar(100)
)
insert into tbl_deleteDuplicate values(1,'a')
insert into tbl_deleteDuplicate values(1,'a')
insert into tbl_deleteDuplicate values(2,'b')
insert into tbl_deleteDuplicate values(3,'c')
insert into tbl_deleteDuplicate values(4,'d')
insert into tbl_deleteDuplicate values(4,'d')
insert into tbl_deleteDuplicate values(5,'e')
insert into tbl_deleteDuplicate values(5,'e')
insert into tbl_deleteDuplicate values(6,'f')
set rowcount 1
while @@rowcount > 0
delete a from tbl_deleteDuplicate a where
(select count(*) from tbl_deleteDuplicate b
where a.emp_id = b.emp_id)>1
set rowcount 0
select * from tbl_deleteDuplicate
set nocount off
2) if value column is duplicate
truncate table tbl_deleteDuplicate
insert into tbl_deleteDuplicate values(1,'a')
insert into tbl_deleteDuplicate values(2,'a')
insert into tbl_deleteDuplicate values(3,'b')
insert into tbl_deleteDuplicate values(4,'c')
insert into tbl_deleteDuplicate values(5,'d')
insert into tbl_deleteDuplicate values(6,'d')
insert into tbl_deleteDuplicate values(7,'e')
insert into tbl_deleteDuplicate values(8,'e')
insert into tbl_deleteDuplicate values(9,'f')
insert into tbl_deleteDuplicate values(10,'f')
insert into tbl_deleteDuplicate values(11,'f')
delete tbl_deleteDuplicate where emp_id not in
(
select max(emp_id) from tbl_deleteDuplicate group by
emp_name having count(emp_name)>1
)
and emp_id not in
(
select max(emp_id) from tbl_deleteDuplicate group by
emp_name having count(emp_name)=1
)
select * from tbl_deleteDuplicate
Is This Answer Correct ? | 1 Yes | 0 No |
Post New Answer View All Answers
How will you decide the active and passive nodes?
You have a table with close to 100 million records recently, a huge amount of this data was updated now, various queries against this table have slowed down considerably what is the quickest option to remedy the situation?
What the different topologies in which replication can be configured?
What are the different types of backups that exist?
How do I port a number to sql server?
When does a workload on SQL Azure get throttled?
How adventureworkslt tables are related?
How the authentication mode can be changed?
What are the different authentication modes in sql server? How can it be changed?
Write the queries for commands like Create Table, Delete table, Drop Table etc.
Which are the third-party tools used in sql server and why would you use them?
Where is trigger in sql server?
Which rendering formats are affected by the pagesize properties?
What is a dataset and what are the different types of datasets?
Are there any preferred steps that need to be taken care of before starting the installation of sql server 2000?