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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

sidsnamesagesgenderPhonenumber
1Abhinav22Male9895678909
2Ramya24Female6687654634
3Preetham21Male9867546453
4Nethranand21Male7675643423
5Naveen23Male6567784532
6Harshita22Female9867546231
7Bindu26Female6563412768
8Nandhini23Female6785674839
9Hashish22Male9453215052
10Rahul21Male9998989898

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

studentidstudentname
1Abhinav
2Ramya
3Preetham
4Nethranand
5Naveen
6Harshitha
7 8Bindhu Nandhini
9Hashish
10Rahul
Select sid AS studentid, sage AS studentage from student;

Output:

Student Table

studentidstudentage
122
224
321
421
523
622
726
823
922
1021

Changing three column names by Alias:

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

Output:

Student Table

studentidstudentnamestudentage
1Abhinav22
2Ramya24
3Preetham21
4Nethranand21
5Naveen23
6Harshita22
7Bindu26
8Nandhini23
9Hashish22
10Rahul21

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

snamestudentdetails
Abhinav1, 22, Male, 9895678909
Ramya2, 24, Female, 6687654634
Preetham3, 21, Male, 9867546453
Nethranand4, 21, Male, 7675643423
Naveen5, 23, Male, 6567784532
Harshita6, 22, Female, 9867546231
Bindu7, 26, Female, 6563412768
Nandhini8, 23, Female, 6785674839
Hashish9, 22, Male, 9453215052
Rahul10, 21, Male, 9998989898

Method II:

Using concat operator

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

Output:

Student Table

snamestudentdetails
Abhinav1, 22, Male, 9895678909
Ramya2, 24, Female, 6687654634
Preetham3, 21, Male, 9867546453
Nethranand4, 21, Male, 7675643423
Naveen5, 23, Male, 6567784532
Harshita6, 22, Female, 9867546231
Bindu7, 26, Female, 6563412768
Nandhini8, 23, Female, 6785674839
Hashish9, 22, Male, 9453215052
Rahul10, 21, Male, 9998989898

Method III:

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

Output:

Student Table

snamestudentdetails
Abhinav1, 22, Male, 9895678909
Ramya2, 24, Female, 6687654634
Preetham3, 21, Male, 9867546453
Nethranand4, 21, Male, 7675643423
Naveen5, 23, Male, 6567784532
Harshita6, 22, Female, 9867546231
Bindu7, 26, Female, 6563412768
Nandhini8, 23, Female, 6785674839
Hashish9, 22, Male, 9453215052
Rahul10, 21, Male, 9998989898

Alias Table Example:

Change Student Table name as Student Data

select * from Student Table AS Student Data;

Output:

      Student Data

sidsnamesagesgenderPhonenumber
1Abhinav22Male9895678909
2Ramya24Female6687654634
3Preetham21Male9867546453
4Nethranand21Male7675643423
5Naveen23Male6567784532
6Harshita22Female9867546231
7Bindu26Female6563412768
8Nandhini23Female6785674839
9Hashish22Male9453215052
10Rahul21Male9998989898

Change Student Table as Student Details

select * from Student Table AS Student Details;

Output:

Student Details

sidsnamesagesgenderPhonenumber
1Abhinav22Male9895678909
2Ramya24Female6687654634
3Preetham21Male9867546453
4Nethranand21Male7675643423
5Naveen23Male6567784532
6Harshita22Female9867546231
7Bindu26Female6563412768
8Nandhini23Female6785674839
9Hashish22Male9453215052
10Rahul21Male9998989898



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