The if, then and else keywords add conditional constructs to an expression.
Note: see wikipedia for more explanation about if then else constructs.
Syntax
if boolean_condition
then value
else value
if boolean_condition then value
else if boolean_condition then value
else if boolean_condition then value
else if boolean_condition then value
else value
Returns
The value after the then of the first condition that returns true.
If all conditions return false, then the value after else is returned.
For combined if..then..else statements, a choose..when construction could be a more readable option.
All 3 segments (if, then, else) are required.
