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Willy Verbiest · Guest

I'm trying to sort a grid by clicking on the title bar but it doesnt work.

procedure TfrmOrdersSelection.DBGrid_OrdersTitleClick(Column: TColumn);

begin

with qryOrders do

begin

DisableControls;

Active := false;

Parameters.ParamByName('SortField').Value := Column.FieldName;

Active := true;

DBGrid_Orders.Columns.RestoreDefaults;

Column.Title.Font.Color := clBlue;

EnableControls;

end;

end;

The SQL for qryOrders is:

SELECT * from tblOrders ORDER BY :SortField

I have created a parameter in the qryOrder with the name 'SortField' and

a start value of 'OrderNo'

The query has no DataSource.

Thanks in advance,

Willy Verbiest

Bill Todd · Guest

You cannot use parameters for database object names. They can only be used
for values.

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Kim S · Guest

Bill Todd wrote:

Del M · Guest

You can use parameters to do sorting but you need to build a special sql
statement for it. What database ? In MS SQL you would have to do this

execute('select * from sometable order by ' + SortParameter)

Kim Stahnke · Guest

I'm using an Access db for this. I've tried to use parameters like in the
WHERE part (:param1...) but it seems not to work at all - and it gives no
error indication either.

Kim

"Del M" <Del.Murray (AT) CreditHawk (DOT) Net> wrote

Bill Todd · Guest

That is not a SQL parameter, but rather a variable. You can use variables for anything when you build the SQL statement dynamically.

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Del M wrote:

Bill Todd · Guest

That is correct. It is not possible. You can only use parameters for a value, not for the name of a database object such as a table or column.

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Kim S wrote:

Bill Todd · Guest

Show us the actual SQL statement that does not work and explain in what way it does not work (get error message, no records returned when you think there should be, ...).

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Kim Stahnke wrote:

Kim S · Guest

Bill Todd wrote:

Bill Todd · Guest

In your previous message you said, "I've tried to use parameters like in
the WHERE part (:param1...) but it seems not to work at all". I do not see
a parameter in the WHERE clause in the SELECT in your latest message so I
do not understand what your question is.

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treok · Guest

There is a possibility:

declare @TheOrder int

set @TheOrder = :param

select * from Table order by case
when @TheOrder = 0 then Field1
when @TheOrder = 1 then Field2 end

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