In Access, the IIF function returns one of two arguments depending on the evaluation of an expression.
The syntax for the IIf function is:
IIf ( expression, truepart, falsepart )
IIf always evaluates both truepart and falsepart, even though it returns only one of them. Because of this, you should watch for undesirable side effects. For example, if evaluating falsepart results in a division by zero error, an error occurs even if expr is True.
expression is the value that you want to test.
truepart is the value returned if expression evaluates to TRUE.
falsepart is the value returned if expression evaluates to FALSE.
IIf ([Price] > 400, "expensive", "cheap") Returns "expensive" if the value in the Price field is
greater than 400. Otherwise, returns "cheap".
If [Price] > 400 Then
This is equivalent to the following IF statement in VBA code. The preceding example uses the IIf function to evaluate the givven expression and returns the word "Expensive" if the amount is greater than 400; otherwise, it returns the word "Cheap".
You can also use the iif function in a query.
SELECT SellerID, BuyerID, Item, IIf([Price]>400,[Price]*1.05,[Price]*1.15) AS Total