SQL Aliases

SQL Aliases:

These are used to give a temporary name for a column or table. These are used to make tables or columns more readable.

• These are used to rename the table or column temporarily. But it does not change in the original database.
• Aliases are used when the table names or column names  are big and they are not readable
• Alias is used with the “AS” Keyword.
• It exists only for the duration of a particular query.

Alias Column Syntax:

select columnname AS aliasname from tablename;

Alias Table Syntax:

select columnname from tablename AS aliasname;

Alias Column Example:

Example:

Student Table

sid	sname	sage	sgender	Phonenumber
1	Abhinav	22	Male	9895678909
2	Ramya	24	Female	6687654634
3	Preetham	21	Male	9867546453
4	Nethranand	21	Male	7675643423
5	Naveen	23	Male	6567784532
6	Harshita	22	Female	9867546231
7	Bindu	26	Female	6563412768
8	Nandhini	23	Female	6785674839
9	Hashish	22	Male	9453215052
10	Rahul	21	Male	9998989898

Changing one column name by Alias:

select sname AS studentname from student;

Output:

Student Table

studentname

Abhinav

Ramya

Preetham

Nethranand

Naveen

Harshitha

Bindhu

Nandhini

Hashish

Rahul

Select sid AS studentid from Student;

Output:

Student Table:

studentid
1
2
3
4
5
6
7
8
9
10

Changing two column names by Alias:

Select sid AS studentid, sname AS studentname from student;

Output:

Student Table

studentid	studentname
1	Abhinav
2	Ramya
3	Preetham
4	Nethranand
5	Naveen
6	Harshitha
7 8	Bindhu Nandhini
9	Hashish
10	Rahul

Select sid AS studentid, sage AS studentage from student;

Output:

Student Table

studentid	studentage
1	22
2	24
3	21
4	21
5	23
6	22
7	26
8	23
9	22
10	21

Changing three column names by Alias:

Select sid AS studentid, sname AS studentname , sage AS studentage from student;

Output:

Student Table

studentid	studentname	studentage
1	Abhinav	22
2	Ramya	24
3	Preetham	21
4	Nethranand	21
5	Naveen	23
6	Harshita	22
7	Bindu	26
8	Nandhini	23
9	Hashish	22
10	Rahul	21

Using Multiple column names as one column name by Alias:

Method I: select * from Student Table AS Student Data;

SELECT sname , sid + ', ' + sage + ', ' + Phonenumber AS studentdetails
FROM student;

Output:

Student Table

sname	studentdetails
Abhinav	1, 22, Male, 9895678909
Ramya	2, 24, Female, 6687654634
Preetham	3, 21, Male, 9867546453
Nethranand	4, 21, Male, 7675643423
Naveen	5, 23, Male, 6567784532
Harshita	6, 22, Female, 9867546231
Bindu	7, 26, Female, 6563412768
Nandhini	8, 23, Female, 6785674839
Hashish	9, 22, Male, 9453215052
Rahul	10, 21, Male, 9998989898

Method II:

Using concat operator

SELECT sname, CONCAT(sid, ', ', sage, ', ', sgender, ‘,’ Phonenumber) AS studentdetails
FROM Customers;

Output:

Student Table

sname	studentdetails
Abhinav	1, 22, Male, 9895678909
Ramya	2, 24, Female, 6687654634
Preetham	3, 21, Male, 9867546453
Nethranand	4, 21, Male, 7675643423
Naveen	5, 23, Male, 6567784532
Harshita	6, 22, Female, 9867546231
Bindu	7, 26, Female, 6563412768
Nandhini	8, 23, Female, 6785674839
Hashish	9, 22, Male, 9453215052
Rahul	10, 21, Male, 9998989898

Method III:

SELECT sname, (sid || ', ' || sage || ' ' || sgender||',' || Phonenumber) AS studentdetails from student;

Output:

Student Table

sname	studentdetails
Abhinav	1, 22, Male, 9895678909
Ramya	2, 24, Female, 6687654634
Preetham	3, 21, Male, 9867546453
Nethranand	4, 21, Male, 7675643423
Naveen	5, 23, Male, 6567784532
Harshita	6, 22, Female, 9867546231
Bindu	7, 26, Female, 6563412768
Nandhini	8, 23, Female, 6785674839
Hashish	9, 22, Male, 9453215052
Rahul	10, 21, Male, 9998989898

Alias Table Example:

Change Student Table name as Student Data

select * from Student Table AS Student Data;

Output:

      Student Data

sid	sname	sage	sgender	Phonenumber
1	Abhinav	22	Male	9895678909
2	Ramya	24	Female	6687654634
3	Preetham	21	Male	9867546453
4	Nethranand	21	Male	7675643423
5	Naveen	23	Male	6567784532
6	Harshita	22	Female	9867546231
7	Bindu	26	Female	6563412768
8	Nandhini	23	Female	6785674839
9	Hashish	22	Male	9453215052
10	Rahul	21	Male	9998989898

Change Student Table as Student Details

select * from Student Table AS Student Details;

Output:

Student Details

sid	sname	sage	sgender	Phonenumber
1	Abhinav	22	Male	9895678909
2	Ramya	24	Female	6687654634
3	Preetham	21	Male	9867546453
4	Nethranand	21	Male	7675643423
5	Naveen	23	Male	6567784532
6	Harshita	22	Female	9867546231
7	Bindu	26	Female	6563412768
8	Nandhini	23	Female	6785674839
9	Hashish	22	Male	9453215052
10	Rahul	21	Male	9998989898