What are the different type of SQL's statements ?
This is one of the frequently asked SQL Interview Questions to freshers. SQL statements are broadly classified into three. They are
- DDL – Data Definition Language
DDL is used to define the structure that holds the data. For example, Create, Alter, Drop and Truncate table.
- DML– Data Manipulation Language
DML is used for manipulation of the data itself. Typical operations are Insert, Delete, Update and retrieving the data from the table. Select statement is considered as a limited version of DML, since it can't change data in the database. But it can perform operations on data retrieved from DBMS, before the results are returned to the calling function.
- DCL– Data Control Language
DCL is used to control the visibility of data like granting database access and set privileges to create tables etc. Example - Grant, Revoke access permission to the user to access data in database.