Nested joins in Teradata - response (1) by Raja_KT

Nested join provides one of the fastest performance compared to other joins, since it does not touch all amps to join tables. It works mostly with PI/SI. The  WHERE clause uses an equijoin  with a constant value( for example  emp.empno=10) for a unique index in one table and those conditions also match some column of that single row to a PI/SI of the second table.

example: 

Select EMP.Ename , DEP.Deptno, EMP.salary

from

EMPLOYEE EMP ,

DEPARTMENT DEP

Where EMP.Enum = DEP.Enum

and EMp.Enum= 1234