Calculations in SQL

Question

I am trying to get a query to perform some math on some user fields so that this query could be made a formatted search for another user field ... all in the BOM.
DECLARE @X1 AS REAL
SET @X1 = $\[$3.U_PartLength\] * $\[$3.U_PartWidth\]
SELECT $\[$3.U_PartLength\], @X1
This code produces an error near "$3.U_PartLength"
The user fields are defined as "Units and Amounts" and "Quantity"
The reason I don't include the calculation in the SELECT statement is that this is the beginning of a complex series of calculations after which I will have to choose the lesser of two values.
Thank you,
Sal

Answer 1

I worked on this all weekend and the only way I can get the system to recognize the UDF is to encase it in square brackets with its own SELECT as follows:
DECLARE @LENGTH AS FLOAT
DECLARE @WIDTH AS FLOAT
DECLARE @YMODE AS NCHAR(1)
SET @WIDTH = CONVERT(FLOAT, (SELECT $\[$3.U_PartWidth\]))
SET @LENGTH = CONVERT(FLOAT, (SELECT $\[$3.U_PartLength\]))
SET @YMODE = (SELECT $\[$3.U_YieldMode\])
I can then do math using the "@" variables.
It seems that the system will only process SAP's special "$" variables through the SELECT command. All the other commands I tried on these "$" variables resulted in error.
Does this make sense?
Sal