>qry_tmp.SQL.Text := 'select Sum(nfi.qtde * nfi.valor) * :wdesc from
>notasfiscaisitens nfi';

>When the line that feed the parameter run, it raises the following
>error: 'strings cannot be multiplied in dialect 3'
>I understand that IBO is trying to prepare the SQL and it is not
>evaluating if the parameter is a text or a numeric. What can I do to
>make this code run?

qry_tmp.SQL.Text := 'select Sum(nfi.qtde * nfi.valor) * cast(:wdesc as double precision) /*or other datatype*/ from
notasfiscaisitens nfi';

HTH,
Set