Know your database – a complex query

I have seen in my life many people learning SQL without prior understanding how databases work. But there are many crucial things that can make writing queries more fun, if it is not fun enough. Optimization in terms of memory use and execution is one of them. I would even say that is the most ...

FiFO with SQL

I am going to create small system/website that will allow me to manage my stocks, and monitor the portfolio. I do not have much of it, but I cannot access the data from wherever I want and it is not so dynamic. Beside the design itself I came across a problem of recreating a FIFO ...

Few Words About Indexes

Writing the previous post it came to my mind, that many people may not be aware that using custom functions in WHERE clauses may be the reason why the index is not used. There are several facts about indexes you should keep in mind: index is most often a b-tree, see one of the Princeton’s lectures ...