>Hi,
>
>CURRENTLEVELS is set as a integer
>BARCODENUMBER is set as a VarChar(13) as that is the max number of a barcode STOCKCONTROLYN is set to >VarChar(1) as it is is either 1 or 0
>
>And yes
>
>UPDATE ProductTable
>SET CurrentLevels = CurrentLevels - '<value>'
>WHERE BarcodeNumber = '<AnotherValue>'
> AND StockControlYN = '1'
>
>That is what I want to do but Firebird is not happy is this function not supported in Firebird?

Just remove the hyphens around <value>, Andy, and it should work:

CurrentLevels - <value>

is supported, whereas

CurrentLevels - '<value>'

isn't - Firebird doesn't allow subtracting a string from an integer and - probably unlike the other databases you mentioned - requires you to correct your query rather than silently assume that you want the string to be treated as if it was an integer.

HTH,
Set