Using SQL ALIAS

SQL ALIAS is used to give a column or table some temporary name which makes these names more readable. Aliases are very helpful in the cases where we use more that one table name in the query.

mysql> SELECT * FROM CUSTOMER;
+----+--------+---------+------+-----------+---------------------+
| ID | FNAME  | LNAME   | AGE  | COUNTRY   | CREATION_DATE       |
+----+--------+---------+------+-----------+---------------------+
|  1 | AKSHAY | KUMAR   |   12 | INDIA     | 2018-05-23 00:16:35 |
|  2 | JONTY  | RHODES  |   40 | CHINA     | 2018-05-18 12:21:12 |
|  3 | JOHNY  | DEPP    |   45 | INDIA     | 2018-05-23 00:16:35 |
|  4 | JESSIE | PINKMAN |   25 | AUSTRALIA | 2018-05-18 12:21:12 |
|  5 | JESSIE | JACKSON |   22 | CANADA    | 2018-05-23 00:16:35 |
|  6 | NICOLE | KIDMAN  |   50 | USA       | 2018-05-18 12:21:12 |
+----+--------+---------+------+-----------+---------------------+
6 rows in set (0.00 sec)

SQL ALIAS syntax for columns names and example -

 SELECT FNAME AS FIRST_NAME, LNAME AS LAST_NAME FROM CUSTOMER;

mysql> SELECT FNAME AS FIRST
+------------+-----------+
| FIRST_NAME | LAST_NAME |
+------------+-----------+
| AKSHAY     | KUMAR     |
| JONTY      | RHODES    |
| JOHNY      | DEPP      |
| JESSIE     | PINKMAN   |
| JESSIE     | JACKSON   |
| NICOLE     | KIDMAN    |
+------------+-----------+
6 rows in set (0.00 sec)

Using above query we have named FNAME column as FIRST_NAME and LNAME column as LAST_NAME. These names are temporary and exists only for the duration of the query.

Using MySQl ALIAS names separated with spaces -

To use space separated ALIAS names like FIRST NAME we need to use quotes around the alias name.

 SELECT FNAME AS 'FIRST NAME', LNAME AS 'LAST NAME' FROM CUSTOMER;

+------------+-----------+
| FIRST NAME | LAST NAME |
+------------+-----------+
| AKSHAY     | KUMAR     |
| JONTY      | RHODES    |
| JOHNY      | DEPP      |
| JESSIE     | PINKMAN   |
| JESSIE     | JACKSON   |
| NICOLE     | KIDMAN    |
+------------+-----------+
6 rows in set (0.00 sec)

SQL ALIAS from table names syntax and example -

  SELECT C.FNAME, C.AGE FROM CUSTOMER AS C;

 +--------+------+
| FNAME  | AGE  |
+--------+------+
| AKSHAY |   12 |
| JONTY  |   40 |
| JOHNY  |   45 |
| JESSIE |   25 |
| JESSIE |   22 |
| NICOLE |   50 |
+--------+------+
6 rows in set (0.00 sec)

In above example you won't see much use of using ALIAS but it would be very helpful when we will use more than one table in a single query which we will see in our next few tutorials specially while using JOINS.