SQL: Column aliases

SQL has the capability to give new labels to the columns in the result set.

 

Syntax 1

SELECT column_name1 alias_name1, column_name2 alias_name2.....FROM {table_name}

 

Syntax 2

SELECT column_name1 AS alias_name1, column_name2 AS alias_name2.....FROM {table_name}

mysql> SELECT * FROM employee;
+--------+------------+-----------+
| emp_id | first_name | last_name |
+--------+------------+-----------+
|      1 | krishna    | gurram    |
|      2 | gopi       | battu     |
|      3 | joel       | chelli    |
+--------+------------+-----------+
3 rows in set (0.00 sec)

 

Example 1: Print first_name as emp_firstName using syntax1.

SELECT emp_id, first_name emp_first_name, last_name FROM employee;

mysql> SELECT emp_id, first_name emp_first_name, last_name FROM employee;
+--------+----------------+-----------+
| emp_id | emp_first_name | last_name |
+--------+----------------+-----------+
|      1 | krishna        | gurram    |
|      2 | gopi           | battu     |
|      3 | joel           | chelli    |
+--------+----------------+-----------+
3 rows in set (0.00 sec)

 

Example 2: Print first_name as emp_firstName using syntax2.

SELECT emp_id, first_name AS emp_first_name, last_name FROM employee;

mysql> SELECT emp_id, first_name AS emp_first_name, last_name FROM employee;
+--------+----------------+-----------+
| emp_id | emp_first_name | last_name |
+--------+----------------+-----------+
|      1 | krishna        | gurram    |
|      2 | gopi           | battu     |
|      3 | joel           | chelli    |
+--------+----------------+-----------+
3 rows in set (0.00 sec)

I prefer to use ‘AS’ keyword, since it is more readable.

 

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