UNION ALL: there is restriction for set
display those who are emp as well managers(INTERSECT)
display those who are not managers (MINUS)
display those depts which do not have emp(MINUS)
dispaly those depts which have emp(INTERSECT) try these……
OUTER-JOIN: used on those tables that keep common columns just like EQUI-JION. but, the o/p will display some extra information which is available in only one of the two tables……
display emp details along with coressponding department details and also display that department details which there are no emp….