Set operators in sql

Set operators
Union
Intersect
Except

Tables:        
    EMP1
  

Classif_ID Classification

1 Pop

2 Country

3 Alternative

4 Metal

7 cad

8 auto

EMP2

Classif_ID Classification

5 cad

6 auto

1 Pop

2 Country

3 Alternative

4 Metal

UNION :
   

select * from  Emp1

union
 select * from Emp2

it will give the results from both the tables with matched and unmatched records
Result

Classif_ID Classification

1 Pop

2 Country

3 Alternative

4 Metal

5 cad

6 auto

7 cad

8 auto

INTERSECT:

 select * from  Emp1
    EXCEPT 
  select * from Emp2
Result:

Classif_ID Classification
1                Pop
2              Country
3              Alternative
4               Metal


EXCEPT

 select * from Emp1

    EXCEPT 

  select * from  Emp2

Result

Classif_ID Classification
7                 cad
8                 auto