Using ParamValue in IF Statement

Hello -

I’m new to the forum and trying to figure out a seemingly simple issue with one of my conditional statements. Essentially, I’m trying to calculate a total based on prompt input from the user. If the user selects a fiscal quarter, then total (value)…else running-count (value). Below is my statement:

IF (ParamValue(‘Qtr’) is missing )

THEN ( total ( [value] for [data item] ) )

ELSE ( running-total ( [value] for [data item 1] , [data item 2] ) )

However, I get this error: ORA-00904: “PARAMVALUE”: invalid identifier

Any suggestions? Thanks in advance.