SQL University: Introduction to Indexes, Part the Third
Nice to see most of you have managed to fight your way through the shoggoths outside to attend another lecture at the Miskatonic branch of SQL University. This will be the third and final part of the introduction to indexes lecture. Please, if you're going mad, step out into the hall. Our previous two lectures introduced the concept of indexes and then talked about two types of indexes, clustered and nonclustered. This lecture will cover the concept of statistics as they relate to indexes. If you followed the previous lecture then you know that indexes are stored in a Balanced Tree or B-Tree structure. You know that this storage mechanism is intended to provide fast retrieval of data. But, how can the query engine inside SQL Server know which index…