How to delete duplicate records from a table?(for suppose in
a table we have 1000 Records in that we have 200 duplicate
Records , so ,how to findout that duplicate Records , how to
delete those Records and arranged into sequence order? one
more thing that there is no primary key at all)
Answers were Sorted based on User's Feedback
Answer / sneha
select distinct * from table into new_table;
delete table;
select * from new_table into table;
| Is This Answer Correct ? | 8 Yes | 6 No |
Answer / cp
DELETE FROM emp WHERE ROWID NOT IN(SELECT MAX(ROWID) FROM
emp GROUP BY empno)
| Is This Answer Correct ? | 2 Yes | 3 No |
Answer / smitha
;with empctc(empid,ename,sal,deptid,ranking)
as
(Select empid,ename,sal,deptid,ranking=Dense_rank() over (
partition by empid,ename,sal,deptid order by NEWID() asc)
from emp
)
delete * from empctc where ranking>1
| Is This Answer Correct ? | 2 Yes | 5 No |
Answer / sirisha
with numbered as(select rowno = row_number() over(partition
by empid order by empid),empname from employee)delete from
numbered where rowno > 1
| Is This Answer Correct ? | 1 Yes | 6 No |
Answer / pooja narang
We will get the duplicate records and insert them into a
new temp table by using below query:
select * into tmp_Employee
from Employee
having count(distinct *) > 1
Now delete the duplicate records from Employee table:
delete from Employee
having count(distinct *) > 1
Now insert the records from tmp_Employee to Employee table:
insert into Employee
select * from tmp_employee
drop table tmp_employee
| Is This Answer Correct ? | 4 Yes | 15 No |
What is difference between process and thread? Explain lazy writer funcationality.
What happens when transaction log is full?
Describe and explain about SQL native client?
How will you find out if there are expensive SQL statements running or not?
What options are available to audit login activity? : sql server security
how to get rank of diffrent student in same table based on newly inserted row in sql server2008
How to create a ddl trigger using "create trigger" statements?
How to delete existing rows in a table?
What is the difference between a Application Server and a Database
How to transfer data from a cursor to variables with a "fetch" statement?
What are the different types of indexes?
What is Stored Procedure? What is Views in sql server? Difference between a User Defined Function and a Stored Procedure Difference between a primary key and a unique key? What is a join and explain different types of joins. Difference between temp table and table variable Difference between Triggers and Stored Procedures Difference between UNION ALL Statement and UNION What is COALESCE / Why do we use COALESCE? Why we use SET ROWCOUNT in Sql How many clustered index can have a table How many types of local tables in SQL SERVER Difference between DELETE and TRUNCATE What is Aggregate Functions? What is Row_Number()? What are Ranking Functions? What is NOLOCK? What is CTE? What are the Advantages of using CTE? What is the STUFF function and how does it differ from the REPLACE function? What are the difference between clustered and a non-clustered index? What are the different index configurations a table can have? Difference between a HAVING CLAUSE and a WHERE CLAUSE? Difference between SET and SELECT Provide all the built in string function of SQL SERVER Difference between char and varchar data types Define candidate key, alternate key, composite key. What are constraints? Explain different types of constraints. What is a self join? Explain it with an example. How will you convert table row to a column comma separated value
Oracle (3253)
SQL Server (4518)
MS Access (429)
MySQL (1402)
Postgre (483)
Sybase (267)
DB Architecture (141)
DB Administration (291)
DB Development (113)
SQL PLSQL (3330)
MongoDB (502)
IBM Informix (50)
Neo4j (82)
InfluxDB (0)
Apache CouchDB (44)
Firebird (5)
Database Management (1411)
Databases AllOther (288)