blogs.conchango.com

Sometimes I will be writing a query and will be faced with the option of writing it in a number of different ways, each of which will give me the result I’m looking for, and the question I always ask is which is most efficient? Now ‘most efficient’ is an ambiguous term to an extent, because we could mean fastest run time, or ...

For any number of reasons which I won’t go into, you may have a need, or desire, to return a value in a query from one row next to a value from another. A typical example might be in a daily sales database, where I want to see yesterday’s total sales against today’s total sales. It is straight forward enough to write the query to ...