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Column Alias in ORACLE

  • Column alias renames a column heading in a query.
  • Its an alternate name for an exiting oracle object.
  • The column alias is specified in the SELECT list by declaring the alias after the column name by using the space separator.
  • Alias heading appears in UPPER casing by default.
  • The alias should be declared in double quotes (“ “).
  • Alias is declared after the column with minimum of one space.
  • The AS keyword can be used between the column name and alias.
  • An alias effectively renames the SELECT list item for duration of the query only.
  • An alias cannot be used, any where in the SELECT list for operational purpose.


Note  : Never consider Alias as a column

Example :=

         1)    Select 20 + 10 Mysum from dual;

         2)   Select ename, sal salary, comm commission from emp;

         3)   Select sal “Basic Salary” from emp;

         4)   Select ename, empno, sal AS Salary from emp;

         5)   Select empno AS Numbers,  
Ename AS Name,
Job AS Designation,
Sal AS  Salary,
Hiredate AS JoinDate
From emp;

- - Either use Numbers or Use as “Number” as a alias, never use Number as a alias.

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