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
|
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