SQL Server DELETE Command
The DELETE is DML Command which is used to delete a specific Record based on Where Clause with condition ; or all the records from the Table, if no Where condition is specified.
As DELETE is a DML Command it will not delete/impact the Structure of a Table.
Syntax:
DELETE FROM Table_name WHERE some_column=some_value
Note:
Notice the WHERE clause in the DELETE syntax. The WHERE clause specifies which record or records that should be deleted. If you omit the WHERE clause, all records will be deleted!
Example:
Suppose we have a EMP Table as follows :
Criteria -I : Deleting a Particular Record :
Delete from EMP WHERE E_Name='Tamatam'
Result :
Criteria -II : Deleting a Multiples Records :
Delete from EMP WHERE Emp_ID IN (1001,1003,1005,1007)
Result :
Criteria -III :To Delete all Records :
It is possible to delete all rows in a table without deleting the Table. This means that the table structure, attributes, and indexes will be remain , only Records will be deleted.
Delete* from EMP
Alert:
Be very careful when deleting records. You cannot undo this statement,unless you create a Transaction with save point.
The DELETE is DML Command which is used to delete a specific Record based on Where Clause with condition ; or all the records from the Table, if no Where condition is specified.
As DELETE is a DML Command it will not delete/impact the Structure of a Table.
Syntax:
DELETE FROM Table_name WHERE some_column=some_value
Note:
Notice the WHERE clause in the DELETE syntax. The WHERE clause specifies which record or records that should be deleted. If you omit the WHERE clause, all records will be deleted!
Example:
Suppose we have a EMP Table as follows :
Emp_ID
|
E_Name
|
Job
|
Dept_ID
|
Salary
|
1001
|
Ravi Teja Reddy
|
Analyst
|
1
|
20000
|
1002
|
Karun
|
Team Lead
|
2
|
35000
|
1003
|
Ravi Kumar Rao
|
Analyst
|
1
|
10000
|
1004
|
Tamatam
|
Team Lead
|
3
|
25000
|
1005
|
Sai Kumar Teja
|
Analyst
|
2
|
15000
|
1006
|
William
|
Manager
|
3
|
50000
|
1007
|
Vikram Teja Reddy
|
Analyst
|
2
|
180000
|
1008
|
Varun
|
Team Lead
|
1
|
33000
|
1006
|
Smith
|
Team Lead
|
3
|
50000
|
Criteria -I : Deleting a Particular Record :
Delete from EMP WHERE E_Name='Tamatam'
Result :
Emp_ID
|
E_Name
|
Job
|
Dept_ID
|
Salary
|
1001
|
Ravi Teja Reddy
|
Analyst
|
1
|
20000
|
1002
|
Karun
|
Team Lead
|
2
|
35000
|
1003
|
Ravi Kumar Rao
|
Analyst
|
1
|
10000
|
1005
|
Sai Kumar Teja
|
Analyst
|
2
|
15000
|
1006
|
William
|
Manager
|
3
|
50000
|
1007
|
Vikram Teja Reddy
|
Analyst
|
2
|
180000
|
1008
|
Varun
|
Team Lead
|
1
|
33000
|
1006
|
Smith
|
Team Lead
|
3
|
50000
|
Criteria -II : Deleting a Multiples Records :
Delete from EMP WHERE Emp_ID IN (1001,1003,1005,1007)
Result :
Emp_ID
|
E_Name
|
Job
|
Dept_ID
|
Salary
|
1002
|
Karun
|
Team Lead
|
2
|
35000
|
1004
|
Tamatam
|
Team Lead
|
3
|
25000
|
1006
|
William
|
Manager
|
3
|
50000
|
1008
|
Varun
|
Team Lead
|
1
|
33000
|
1009
|
Smith
|
Team Lead
|
3
|
50000
|
Criteria -III :To Delete all Records :
It is possible to delete all rows in a table without deleting the Table. This means that the table structure, attributes, and indexes will be remain , only Records will be deleted.
Delete* from EMP
Alert:
Be very careful when deleting records. You cannot undo this statement,unless you create a Transaction with save point.
--------------------------------------------------------------------------------------------------------
No comments:
Post a Comment
Hi User, Thank You for visiting My Blog. Please post your genuine Feedback or comments only related to this Blog Posts. Please do not post any Spam comments or Advertising kind of comments which will be Ignored.