Explain and analyze

- Now, I'm starting where I left off … in the last video. … You'll notice, I have some create table statements, … and insert commands, in my query window. … So, I'm going to leave those, … and I'm just going to create another query window, … so I'll have a clear window to start with. … Now, one of the first steps, … in optimizing queries, … is understanding how they're executing. … Remember, SEQUEL is declarative. … So, for example, … here is a simple declarative query. … We'll type "SELECT * FROM staff". … Now a query is a declarative statement … that must be mapped into … a procedural execution plan. … So we want to understand what that plan looks like, … and from there we can do a variety of things … to our data model, and query to try … and make it more efficient. … So let's just take a look at the results … of this select statement. … We'll notice here that there are … a thousand rows that are returned, … and if we take a look here … we can see the nine columns, … that we saw on the previous video, …