>what is the difference between full join , inner join ,left outer join , right outer join ?

Inner Join: All record from two sets that match each other. No unmatched records in result.
Left Join: All records from the left set and those records from the right set that match.
Right Join: All records from right set and those recordsf rom left set that match.
Full Join: All record from two sets that match each other. Plus the unmatched records from both sets.