function TdmMain.DBValue(ASql, ADefault: string): string;
var
qryData: TADOQuery;
begin
qryData := TADOQuery.Create(Self);
try
qryData.Connection := ConnMain;
qryData.SQL.Text := ASql;
qryData.Open;
if qryData.IsEmpty Then
Result := ADefault
else
Result := qryData.Fields[0].AsString;
qryData.Close;
finally
qryData.Free;
end;
end;