TStream实现多表查询

TStream实现多表查询

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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;