MySQL count unique values in 2 fields

MySQL count unique values in 2 fields

References

Reference NO 1

http://stackoverflow.com/questions/15165661/mysql-count-unique-values-in-2-fields

Reference NO 2

http://stackoverflow.com/questions/12188027/mysql-select-distinct-multiple-columns

Reference NO 3

http://forums.devshed.com/mysql-help-4/using-count-distinct-column-2137.html

Reference NO 4

http://www.dbasupport.com/forums/showthread.php?11349-specifying-multiple-distinct-columns-in-a-COUNT()-function

Reference NO 5

http://forums.codewalkers.com/database-help-83/how-to-count-distinct-elements-mysql-83529.html

Reference NO 6

http://www.onlamp.com/pub/a/onlamp/excerpt/mysqlckbk/index1.html?page=2

Reference NO 7

http://www.daniweb.com/web-development/databases/mysql/threads/311910/count-and-print-unique-values-in-column

Reference NO 8

http://bugs.mysql.com/bug.php?id=21705