Need an calculated expression for an access 2016 report

[lkyinc]

I am a blood drive leader, I'm trying to extract certain data from a table of all our blood drivers.



The three fields being used are: [unitscollected] (numberical), [tag] (text), and [successfuldonation] (text)

I need an expression for a calculated field in the report footer. Here's what I have tried: =Sum([unitscollected]) (iif([successfuldonation] ="YES" AND [tag] = "P", "*", Null)))

I keep getting syntax error "operator without an operand"

I appreciate your help

Kent

[June7]

=Sum(IIf([successfuldonation] = "Yes" AND [tag] = "P", [unitscollected], Null))

[lkyinc]

=Sum(IIf([successfuldonation] = "Yes" AND [tag] = "P", [unitscollected], Null))

It works great. Thank you. Kent