Re: Maximum length of SQL statement in Delphi
Posted by webmaster Guido on July 21, 2004
In Reply to: Maximum length of SQL statement posted by Vincent on July 20, 2004:
: Hi everyone. Does anyone know of a way to overcome the 4095 character (4K) limit of a SQL statement in Delphi? I need to code a very long SQL statement, using a TQuery component, adding lines by means of query1.SQL.Add(). I am thinking that this may be a BDE limitation. Any suggestions would be appreciated.
It's a limitation of Delphi's BDE. Limits of according to Borland:
64K Size of SQL statement (RequestLive=False)
Alternative: code it yourself. Using a TTable component, step through all the records and copy the records that meet your conditions to a temporary table. Next, work with the temporary table.
var Cond1, Cond2, Cond3: Boolean; .... Table1.First; while not Table1.EOF do begin Cond1 := (FieldA.Value = ...) and (FieldB.Value > ...) and ...; Cond2 := (FieldC.Value > FieldD.Value); Cond3 := and_so_on; if Cond1 and Cond2 and Cond3 then Append_Record_To_Table2; Table1.Next; end;
This technique is also useful for debugging any large SQL statement. Even if it's not too big for Delphi, it might be too complex for the Delphi programmer :-p So, replace it with Pascal code and now you can add calculations to check values, set breakpoints, step through the code,... whatever is necessary to pinpoint the error.
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