SQL - TRUNCATE TABLE

The SQL TRUNCATE TABLE statement is used to delete complete data from an existing table. The SQL DROP TABLE statement can also be used to delete complete data of a table but it will delete whole table structure from the database. Hence, SQL TRUNCATE TABLE statement is useful when a table need to be emptied but the table structure is retained.

Note: Be careful before truncating a table. Once deleted, all data stored in that table will be lost forever!.

Syntax

The syntax of the TRUNCATE TABLE is given below:

TRUNCATE TABLE table_name;

Example:

Consider a database tables called Employee with the following records:

EmpID	Name	City	Age	Salary
1	John	London	25	3000
2	Marry	New York	24	2750
3	Jo	Paris	27	2800
4	Kim	Amsterdam	30	3100
5	Ramesh	New Delhi	28	3000
6	Huang	Beijing	28	2800

The description of the table can be checked using DESC command as shown below:

DESC Employee;

Field	Type	Null	Key	Default
EmpID	int(11)	No	PRI
Name	varchar(255)	No
City	varchar(100)	Yes		NULL
Age	int(11)	Yes		NULL
Salary	decimal(18,2)	Yes		NULL

To truncate this table, the SQL code is shown below:

TRUNCATE TABLE Employee;

After truncating the table, the DESC command will still show the same structure as shown above but the table contains no records.

SELECT * from Employee;

This result of the above code will be:

EmpID	Name	City	Age	Salary