delphi TStream实现多表查询

TStream实现多表查询

function TynFiredac.QuerySQLS(const ASQL, ASQL2: string; AStorageFormat: string = 'binary'): TStream;

var

  LStream1, LStream2: TStream;

begin

  Result := nil;

  if ASQL = '' then

    Exit;

  Result := TMemoryStream.Create;

  LStream1 := TMemoryStream.Create;

  LStream2 := TMemoryStream.Create;

  try

    try

      FDQuery1.Close;

      FDQuery1.SQL.Clear;

      FDQuery1.SQL.Add(ASQL);

      FDQuery1.Open;

      FDQuery1.SaveToStream(LStream1, TynStream.GetFDStorageFormat(AStorageFormat));

      LStream1.Position := 0;

      FDQuery1.Close;

      FDQuery1.SQL.Clear;

      FDQuery1.SQL.Add(ASQL2);

      FDQuery1.Open;

      FDQuery1.SaveToStream(LStream2, TynStream.GetFDStorageFormat(AStorageFormat));

      LStream2.Position := 0;

      TynStream.MergeStream(Result, LStream1, LStream2);

    except

      on E: Exception do

      begin

        Result := nil;

        Log.WriteLog('TynFiredac.QuerySQLs ' + E.Message);

      end;

    end;

  finally

    FDQuery1.Close;

    FDConnection1.Close;

    LStream1.Free;

    LStream2.Free;

  end;

end;

 来源：https://www.cnblogs.com/hnxxcxg/p/9947636.html