Linux Today: Linux News On Internet Time.

Three Ways to Identify Non-matching Records in MySQL

May 11, 2011, 08:09 (0 Talkback[s])

"There are many times as a database developer and administrator that you'll want to know what entities are being excluded from a straight table join.

"For instance, it would be instructive for management to identify sales people who haven't received any bonuses, as these might be deemed to be the underperformers. To provide the requestor with the statistics, you'll have to determine which sales people are absent from the bonuses table. This is commonly referred to as a Non-matching query, although it is sometimes called a Subtract or Set Difference query as well."

Complete Story

Related Stories: