Manipulating Data Results Using Conditional SQL
In previous chapters, we learned how to use the WHERE clause and a series of functions to filter down and format the data results. Now, what if we must give certain field values a new definition to make them more understandable? For example, the state names in the database were stored in abbreviations, however, the reports the data serve are meant to serve international stakeholders. So then, how can we present IL as Illinois and CA as California without having to add a column into the database taking up permanent storage space? Or perhaps, for better grouping purposes, we want to be able to provide the report users with a country-level sales revenue number instead of just state-level details. This is when we head into the conditional query world, by defining the grouping rules at query runtime.
In this chapter, we will learn about when and how to use the CASE, COALESCE, and ISNULL statements, noting the advantages and disadvantages...
