So you think you can count
5. Problems with subtraction
Round and other functions
Revision and practice


Great! As you might expect, these simple operations can also get very tricky. Let's discuss them now.

We'll start with subtraction.


For a character Mnah select name, weight, height and the result of the following calculation: weight - height - weight + height. It should equal 0, right?

Stuck? Here's a hint!

Introduce a WHERE clause and remember to put the character name in apostrophes.