⟩ Can we use a having clause in groupby clause?
having cluase can only be used with group by clause.
if there are 500 records i will give rownumber<250 then it
fetch 249 records.
NVL2( string1, value_if_NOT_null, value_if_null )
if string1 is not null then it returns 'value_if_NOT_null'
and if string1 is null then it returns 'value_if_null'.
if there are four tables without using cartesian we have n-
1 join where n is number of tables. i.e 4-1=3 join required
four tables without using cartesian.
