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SQL Aliases



You can specify aliases for table names or column names by using SQL.


SQL alias

Using SQL, you can specify aliases for table names or column names.

Basically, aliases are created to make column names more readable.

SQL alias syntax for columns

SELECT column_name AS alias_name
FROM table_name;

SQL alias syntax for tables

SELECT column_name (s)
FROM table_name AS alias_name;


Demo database

In this tutorial, we will use the welookups sample database.

Here is the data from the "Websites" table:

+----+--------------+---------------------------+-------+---------+
| id | name         | url                       | alexa | country |
+----+--------------+---------------------------+-------+---------+
| 1  | Google       | https://www.google.cm/ | 1     | USA     |
| 2  | Indiatimes          | https://www.Indiatimes.com/| 13    | IN            |
| 3  | zomato      | http://www.zomato.com/ | 4689  | IN            |
| 4  | indiamart          | http://indiamart.com/      | 20    | IN            |
| 5  | Facebook     | https://www.facebook.com/| 3     | USA     |
| 7  | stackoverflow | http://stackoverflow.com/|   0 | IND     |
+----+---------------+---------------------------+-------+---------+

Here is the data of the "access_log" website visit log:

mysql> SELECT * FROM access_log;
+-----+---------+-------+------------+
| aid | site_id | count | date       |
+-----+---------+-------+------------+
|   1 |       1 |    45 | 2016-05-10 |
|   2 |       3 |   100 | 2016-05-13 |
|   3 |       1 |   230 | 2016-05-14 |
|   4 |       2 |    10 | 2016-05-14 |
|   5 |       5 |   205 | 2016-05-14 |
|   6 |       4 |    13 | 2016-05-15 |
|   7 |       3 |   220 | 2016-05-15 |
|   8 |       5 |   545 | 2016-05-16 |
|   9 |       3 |   201 | 2016-05-17 |
+-----+---------+-------+------------+
9 rows in set (0.00 sec)


Column alias example

The following SQL statement specifies two aliases, one for the name column and one for the country column. Tip: If the column name contains spaces, double quotes or square brackets are required:

Example

SELECT name AS n, country AS c
FROM Websites;

Execution output:

In the following SQL statement, we combine the three columns (url, alexa, and country) and create an alias named "site_info":

Example

SELECT name, CONCAT (url, ',', alexa, ',', country) AS site_info
FROM Websites;

Execution output:



Alias instance of the table

The following SQL statement selects the records visited by "welookups Tutorial". We use the "Websites" and "access_log" tables and give them the table aliases "w" and "a", respectively (to make SQL shorter by using aliases):

Example

SELECT w.name, w.url, a.count, a.date
FROM Websites AS w, access_log AS a
WHERE a.site_id = w.id and w.name = "welookups tutorial";

Execution output:

Same SQL statement without alias:

Example

SELECT Websites.name, Websites.url, access_log.count, access_log.date
FROM Websites, access_log
WHERE Websites.id = access_log.site_id and Websites.name = "welookups tutorial";

Execution output:

Use of aliases is useful in the following situations:

  • More than one table is involved in the query
  • A function was used in the query
  • Column names are long or readable
  • Need to combine two or more columns