Difference between INTERSECT and INNER JOIN?




Sno
Intersect
Inner join
1
It is SET operator
It is JOIN operator
2
It return duplicates
It remove duplicates
3
 It never return NULL values, If exists
 It return NULL values, If exists
4
 It matches Limited set of columns
 It compares all rows between two sets


Examples:



CREATE TABLE #a (id INT)

CREATE TABLE #b (id INT)

INSERT INTO #a VALUES (1), (NULL), (2)
INSERT INTO #b VALUES (1), (NULL), (3), (1)


select * from #a                    select * from #b

#A #B
id id
1 1
NULL NULL
2 3

1
1)select #a.id from #a INNER JOIN #b on #a.id=#b.id
         o/p) 1
                 1

2) select * from #a INTERSECT  select * from #b
       o/p)  NULL
               1











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