Newbie Question about empty fields

[Nugget]

G'day I'm new to this and can not for the life of me find out what I'm doing wrong.

I have made a database the main dispatch form has a portal in it and I'm stuck on a few of the fields. What I want to do it multiply Quantity by the perunit1 price and put the result into perunit3 field for cash customers but I want the perunit3 field to remain blank if I don't enter a price into perunit1.

Don't laugh to hard but this is what I've tried so far.

If(IsEmpty(PerUnit1);"";"PerUnit3=Quantity*PerUnit1")

This always gives me $31 no mater what I put in the perunit1 field.

This one always gives me a total of $1

If (PerUnit1 ="";"";"Quantity * PerUnit1")

Can anyone help me out please?

[comment]

Try =

If ( not IsEmpty ( PerUnit1 ) ; Quantity * PerUnit1 )

[Nugget]

You are awesome. Thanks heaps for the quick and the help. Works Perfect. :(

[bruceR]

You're not formatting the calculation correctly. Two errors.

1. You are applying quotes when you shouldn't.

2. You are writing out the "left side" of the equation, that is not how calcs are written.

You have apparently set the field type as number. That part is correct; but because of the quotes, you are basically asking "show me the digits you see in this string of text" and FileMaker is doing what you asked. It is returning the 3 and 1 characters.

No:

If(IsEmpty(PerUnit1);"";"PerUnit3=Quantity*PerUnit 1")

Yes:

If(IsEmpty(PerUnit1);""; Quantity*PerUnit 1 )

Or:

Case( PerUnit1; Quantity*PerUnit 1 )

[Nugget]

Only 2 things wrong is pretty good for someone that has no idea. I'm sick of the way I do dockets at work (everyone one is on an excel spreadsheet and a nightmare when trying to find an old order) but my lazy bosses won't come up with an easier way of doing it so I'm trying to do it on my own. Tried with Access but thats to hard. Filemaker pro seems a lot easier for someone simple like me. If I can get this all working I won't mind coming to work so much. Thanks again for all the help in info.