Explain outer join?
Outer Join - If there are any values in one table which do not have corresponding value(s) in the other, in an equi-join which will not be chosen. Such rows could be forcefully selected through using the outer join. The corresponding columns for in which row will have NULLs. There are actually three forms of the outer-join operation: left outer join ( X), right outer join (X ) and full outer join ( X ).