From the past I have been trying to get this solution by SQL, but I couldn't find or figure the solution using SQL.    From my understanding, SQL is given constraint or instruction within field inside database structure, but I can't figure how to output things into Delphi components. May be there is but I just can't not figure it out

I think you should use data-aware components, e.g. TDBEdit instead of TEdit. In your case since the fields are unknow until the query is executed (or you can add type fields to the query ), class="code"> DBEdit1.Datasource := DataSource1; DBEdit1.DataField.FieldName := Query1.Fields[0].FieldName;

and I found alternative approach using Delphi: procedure TOrderSytem.QtnEditExit(Sender: TObject); var value1, value2 : real; begin tTempShow.Append; tTempShow.FieldByName('DishID').Value := tSearch.FieldValues['ID']; tTempShow.FieldByName('DishName').Value := tSearch.FieldValues['DishName']; tTempShow.FieldByName('Quantity').Value := Qtnedit.Text; value1 := tSearch.fieldValues['Price']; value2:= tTempShow.FieldValues['quantity'] * value1; tTempShow.FieldValues['Subtotal'] := value2; tTempShow.Post; end; It works for calculating subtotal, but! I can work out the total: Is there a Sum(Whole Column) of table using Delphi syntex?? Urgent! Plz help!!

引言: Is there a Sum(Whole Column) of table using Delphi syntex??

The simplest way is to execute a SQL statement and get the sum. For table (i.e. BDE/ADO table), you need to calculate it yourself. There exists a way in using client dataset and aggregate fields for this kind of caluclation, this is more complicated and I think you should try the SQL way first.

I have the SQL solution, but I want the output is actually on a Tedit?    My sql solution: select OrderNumber, Sum(Price * Quantity) as OrderTotal from Detail D, Menu M  where D.FoodID = M.FoodID group by OrderNumber    but I can't output the result on a Tedit, it is always has been my problem.plz plz my lord..

Using a TDBEdit as I suggested before should work... If you want to use a TEdit, then: Edit1.Text := Query1.Fields[1].AsString;

.Fields[1].AsString; <---- what's this bit means? can u explain?

use put this coding in a button using this qTotal query: select D.OrderNumber, Sum(Price * Quantity) as Total from DetailTable D, Menu M where D.DishID = M.ID group by D.OrderNumber with Edit3.Text := qTotal.Fields[1].AsString; something shows up, but it is '0' why?

Final Finaly how can I print stuff using Query??

引言:.Fields[1].AsString; <---- what's this bit means? can u explain?

Please refer to the help of TField since xxx.Fields[x] is a TField.

引言:something shows up, but it is '0'

Data is 0... Please check by executing the SQL using SQL Explorer.

引言:how can I print stuff using Query??

I guess you want a good looking way to print it, right? Perhaps you should try those reporting systems, e.g. Rave Report/Quick Report; they come with Delphi 7.

can Rave relate use of Query as well? can u teach me??

引言:can Rave relate use of Query as well? can u teach me??

Both Rave Report/Quick Report and other report tools are always working on data (i.e. query, table); and it is why they exist. I am sorry I can't help you here since I never use any reporting tools, what I did was do it ALL (query/preview/print) by myself in the past. Try playing with Rave first since Borland seems would like to drop Quick Report...