The SQL TRUNCATE TABLE command is used to delete complete data from an existing table.
You can also use DROP TABLE command to delete complete table but it would remove complete table structure form the database and you would need to re-create this table once again if you wish you store some data.
Truncate table is faster and uses lesser resources than DELETE TABLE command.
Drop table command can also be used to delete complete table but it deletes table structure too. TRUNCATE TABLE doesn't delete the structure of the table.
The basic syntax of TRUNCATE TABLE is as follows:
TRUNCATE TABLE table_name;
And if truncate the data of employee table
TRUNCATE TABLE Employee
Note: The rollback process is not possible after truncate table statement. Once you truncate a table you cannot use a flashback table statement to retrieve the content of the table.
If you want to copy a SQL table into another table in the same SQL server database, it is possible by using the select statement.
The syntax of copying table from one to another is given below:
Select * into <destination table> from <source table>
For example, you can write following command to copy the records of hr_employee table into employee table.
Select * into admin_employee from hr_employee;
Note: SELECT INTO is totally different from INSERT INTO statement.