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SQL UNION Operator

Anonymous User 1778 03-Nov-2015
what is use of union and union all Operator in sqlserver.
.net sql server 
Updated on 03-Nov-2015
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Anonymous User

Anonymous User

03-Nov-2015

The UNION operator is used to combine the result-set of two or more SELECT statements.

Notice that each SELECT statement within the UNION must have the same number of columns. The columns must also have similar data types. Also, the columns in each SELECT statement must be in the same order.

SQL UNION Syntax

SELECT column_name(s) FROM table1
UNION
SELECT column_name(s) FROM table2;

Note: The UNION operator selects only distinct values by default.

SQL UNION ALL Syntax

SELECT column_name(s) FROM table1
UNION ALL
SELECT column_name(s) FROM table2;

Note : The UNION operator selects All (duplicate values also) values by default.

For Exp:

Union

SELECT City FROM Customer

UNION 



SELECT City FROM Supplier



ORDER BY City

Result :

  
SQL UNION Operator
 

 
Result:
 
SQL UNION Operator

 

 Union All 

SELECT City FROM Customer

UNION 

SELECT City FROM Supplier

ORDER BY City

 

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