union in sql server

Question

with example

Shweta Lodha · Answer

The SQL UNION operator combines the result of two or more SELECT statements. The SQL UNION Operator 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. To allow duplicate values use the ALL keyword with UNION. SQL UNION ALL Syntax SELECT column_name(s) FROM table1 UNION ALL SELECT column_name(s) FROM table2 ; PS: The column names in the result-set of a UNION are usually equal to the column names in the first SELECT statement in the UNION. URL: http://technet.microsoft.com/en-us/library/ms180026.aspx http://www.w3schools.com/sql/sql_union.asp