Selecting Data – Part 4

Today, I am continuing our exploration of the SELECT reserved word by talking about sub-queries. A sub-query is a query that is nested inside a SELECT, INSERT, UPDATE, or DELETE statement, or inside another sub-query. Sub-queries can be used anywhere an expression is allowed or can be nested inside another sub-query. I will be using the AdventureWorks Sample database supplied by Microsoft during this talk.

One usage a sub-query is with comparison operators in the where clause. The example below returns all the sales people by name and id…