What the difference between UNION and UNIONALL? Anonymous User293024-Mar-2012mssql servermssql server Updated on 21-Sep-2020
Prashant K
11-May-2012Both commands combines the tables with common fields except ‘UNION’ displays all the rows from objects without looking at duplicate records whereas ‘UNION ALL’ looks for it and displays only unique records. Thus ‘UNION’ it slower than ‘UNION ALL’
Anonymous User
24-Mar-2012Union will remove the duplicate rows from the result set while Union All doesn’t.