LO1: Purpose of Union and Union All LO2: Difference between Union and Union All LO3: Difference between Joins and Union Prerequisite: Joins Union and Union All is used to combine the result set of two or more queries. To combine two results set, the column list in the select columns, data types, and order of the columns need to be same. Let’s say we have the two table tblcustomer1 and tblcustomer2 with the identical columns in each table. To combine these two result set into one we can use the Union All . select * from tblcustomer1 Union All select * from tblcustomer2 In the above screen, all the rows combined into one result set. Now let’s try to use the Union only and observe the result set. select * from tblcustomer1 Union select * from tblcustomer2 In the above screen, the duplicate row is included only once and the result also gets sorted. Note: In the case of Union, Duplicate rows only get removed from the re...