How do you select the maximum value of a column in a DBGrid when displayed through a query?
(query SQL:select max(CustNo) from customer, and get error message:”the table is read only”)
You have to go to the underlying table itself. You can’t do this through a DBGrid. Remember, data control objects like TDBGrid are used purely for display and real-time editing. They don’t really do any summarization.
But you can work around this by creating a calculated field that will perform the Max calculation for you in the OnCalcFields event. Read more about this in the online help.