SQLite - NULL Values

SQLite - Triggers

You can rename a table or a column temporarily by giving another name, which is known as ALIAS. The use of table aliases means to rename a table in a particular SQLite statement. Renaming is a temporary change and the actual table name does not change in the database.

The column aliases are used to rename a table's columns for the purpose of a particular SQLite query.

Syntax

Following is the basic syntax of table alias.

SELECT column1, column2....
FROM table_name AS alias_name
WHERE [condition];

Following is the basic syntax of column alias.

SELECT column_name AS alias_name
FROM table_name
WHERE [condition];

Example

Consider the following two tables, (a) COMPANY table is as follows −

sqlite> select * from COMPANY;
ID          NAME                  AGE         ADDRESS     SALARY
----------  --------------------  ----------  ----------  ----------
1           Paul                  32          California  20000.0
2           Allen                 25          Texas       15000.0
3           Teddy                 23          Norway      20000.0
4           Mark                  25          Rich-Mond   65000.0
5           David                 27          Texas       85000.0
6           Kim                   22          South-Hall  45000.0
7           James                 24          Houston     10000.0

(b) Another table is DEPARTMENT as follows −

ID          DEPT                  EMP_ID
----------  --------------------  ----------
1           IT Billing            1
2           Engineering           2
3           Finance               7
4           Engineering           3
5           Finance               4
6           Engineering           5
7           Finance               6

Now, following is the usage of TABLE ALIAS where we use C and D as aliases for COMPANY and DEPARTMENT tables respectively −

sqlite> SELECT C.ID, C.NAME, C.AGE, D.DEPT
        FROM COMPANY AS C, DEPARTMENT AS D
        WHERE  C.ID = D.EMP_ID;

The above SQLite statement will produce the following result −

ID          NAME        AGE         DEPT
----------  ----------  ----------  ----------
1           Paul        32          IT Billing
2           Allen       25          Engineering
3           Teddy       23          Engineering
4           Mark        25          Finance
5           David       27          Engineering
6           Kim         22          Finance
7           James       24          Finance

Consider an example for the usage of COLUMN ALIAS where COMPANY_ID is an alias of ID column and COMPANY_NAME is an alias of name column.

sqlite> SELECT C.ID AS COMPANY_ID, C.NAME AS COMPANY_NAME, C.AGE, D.DEPT
        FROM COMPANY AS C, DEPARTMENT AS D
        WHERE  C.ID = D.EMP_ID;

The above SQLite statement will produce the following result −

COMPANY_ID  COMPANY_NAME  AGE         DEPT
----------  ------------  ----------  ----------
1           Paul          32          IT Billing
2           Allen         25          Engineering
3           Teddy         23          Engineering
4           Mark          25          Finance
5           David         27          Engineering
6           Kim           22          Finance
7           James         24          Finance

SQLite - ALIAS Syntax