SQL Server

A primary key is used to uniquely identifies a record. A key is used to sort, compare and create a relationship between records. There are some basic rules to follow …

If you wanted to search a bunch of values, you would write a WHERE clause with the values joined by the OR operator. A more readable WHERE clause would be …

If you need to change the name of the column returned by a query use can use the “AS” clause. Without the AS clause, the returned column name will be …

To download the Northwind sample database, go here. http://www.microsoft.com/en-us/download/details.aspx?id=23654   To download the Adventure Works sample database, go here. http://www.microsoft.com/en-us/download/details.aspx? Id=10679