Alias is used to give an alias name to a table or a column. This is quite useful in case of large or complex queries. Alias is mainly used for giving a short alias name for a column or a table with complex names.

Syntax of Alias for table names,
SELECT column-name
from table-name
as alias-name
Following is an Example using Alias,
SELECT * from Employee_detail as ed;
Alias syntax for columns will be like,
SELECT
column-name as alias-name
from
table-name
Example using alias for columns,
SELECT customer_id as cid from Emp;


Also ,if you want to display column name with space like Customer Name, then need to use double quotes (“”)

Like

SELECT customer_id as “Customer ID” from Emp;

Also _ (underscore) allowed in the alias name.

Like

SELECT customer_id as Customer_ID from Emp;


Example of Alias in SQL Query
Consider the following two tables,

The class table,
ID
Name
1
abhi
2
adam
3
alex
4
anu
5
ashish

The class_info table,
ID
Address
1
DELHI
2
MUMBAI
3
CHENNAI
7
NOIDA
8
PANIPAT


Below is the Query to fetch data from both the tables using SQL Alias,
SELECT C.id, C.Name, Ci.Address from Class as C, Class_info as Ci where C.id=Ci.id;

Result table look like,
ID
Name
Address
1
abhi
DELHI
2
adam
MUMBAI
3
alex
CHENNAI

0 Comments:

Post a Comment