NULL is a fickle beast, and for the people not accustomed to how it works in SQL, it can create many problems (read: incorrect data output). This is especially true for those coming from ...

-- List the teachers who have NULL for their department. -- Use COALESCE to print the mobile number. Use the number '07986 444 2266' if there is no number given. Show teacher name and mobile number or ...

Is your SQL drawing a blank? It’s NULL a surprise! The title of this post is a play on words, but very appropriate. We are going to discuss the inconsistent results, as well as performance ...

Spread the loveNULL in SQL is a powerful concept, representing the absence of a value. It’s used when data is unavailable or unknown, but its usage requires careful consideration. The first step is ...