SQL COALESCE Function
The first time I saw the term COALESCE in a SQL manual, I thought it was a scientific function for some complex calculation. However, later I found that it is a straightforward and handy function. In this article, I will show several examples to explain how to use the COALESCE function.
THE REASON BEHIND COALESCE: THE NULL VALUE
Before go deep with COALESCE function, the reader needs to understand how the NULL value works in some expressions. A NULL value in a table column means ...