fdLocalSql可以对fdMemTable内存表进行SQL查询（可以对多个fdMemTable内存表进行联表查询哦），fdLocalSql使用SQLITE引擎，而FIREDAC驱动SQLITE，连SQLITE驱动DLL都不需要附带的。

所有设置用FormCreate里用代码

 

procedure TForm6.FormCreate(Sender: TObject);
begin
 FDConnection1.Open('DriverID=SQLite');

  FDLocalSQL1.Connection:= FDConnection1;
  FDLocalSQL1.Active:=true;

  FDMemTable1.FieldDefs.Add('aID', ftInteger, 0, True);
  FDMemTable1.FieldDefs.Add('aName', ftString, 20, false);

FDMemTable1.CreateDataSet();
FDMemTable1.AppendRecord([101, 'aaa']);
FDMemTable1.AppendRecord([102, 'bbb']);
FDMemTable1.AppendRecord([102, 'bbb']);
FDMemTable1.AppendRecord([102, 'bbb']);
FDMemTable1.AppendRecord([103, 'ccc']);

FDMemTable1.LocalSQL:= FDLocalSQL1;
FDMemTable1.Active:=true;

FDQuery1.Connection:= FDConnection1;
FDQuery1.SQL.Text:='select * from FDMemTable1 where aid>101 ' ;
FDQuery1.Active:=true;

DataSource1.DataSet:= FDQuery1;
DbGrid1.DataSource:= DataSource1;
end; 

 2]可以设置多个内存表，FDMemTable1,FDMemTable2

//================================ FDMemTable1 =====================================
  FDMemTable1.FieldDefs.Add('aID', ftInteger, 0, True);
  FDMemTable1.FieldDefs.Add('aName', ftString, 20, false);

FDMemTable1.CreateDataSet();
FDMemTable1.AppendRecord([101, 'aaa']);
FDMemTable1.AppendRecord([102, 'bbb']);
FDMemTable1.AppendRecord([102, 'bbb']);
FDMemTable1.AppendRecord([102, 'bbb']);
FDMemTable1.AppendRecord([103, 'ccc']);

FDMemTable1.LocalSQL:= FDLocalSQL1;
FDMemTable1.Active:=true;
//--------------------------- FDMemTable2 --------------------------------------
  FDMemTable2.FieldDefs.Add('aID', ftInteger, 0, True);
  FDMemTable2.FieldDefs.Add('aName', ftString, 20, false);

FDMemTable2.CreateDataSet();
FDMemTable2.AppendRecord([201, 'aaa']);
FDMemTable2.AppendRecord([102, 'bbb']);
FDMemTable2.AppendRecord([202, 'bbb']);
FDMemTable2.AppendRecord([102, 'bbb']);
FDMemTable2.AppendRecord([103, 'ccc']);

FDMemTable2.LocalSQL:= FDLocalSQL1;
FDMemTable2.Active:=true;
//==================================================================================
FDQuery1.Connection:= FDConnection1;
FDQuery1.SQL.Text:='select * from FDMemTable1, FDMemTable2 where FDMemTable1.aID=FDMemTable2.aID ' ;  //这里写SQL语句
FDQuery1.Active:=true;