AggregatesRuntime

unit AggregateRuntime

uses DBclient,
Vcl.StdCtrls,sysutils,
     FireDAC.Stan.Intf, FireDAC.Stan.Option, FireDAC.Stan.Param,
     FireDAC.Stan.Error, FireDAC.DatS, FireDAC.Phys.Intf, FireDAC.DApt.Intf, FireDAC.Stan.Async, FireDAC.DApt,
     FireDAC.Comp.DataSet, FireDAC.Comp.Client,DB;

 Type
  TypeAggregateERROR = class(Exception);

TAggregateRetorne = (ftSomar,ftMaxima,ftContar,FtMedia);

TOperacoes =class
   class function  Retornar(Dataset: TFDquery;
                   const cField: String; Tipo: TAggregateRetorne): Currency; overload;
   class function  Retornar(Dataset: TClientDataset;
                   const cField: String; Tipo: TAggregateRetorne): currency; overload;

  end;

class function TOperacoes.Retornar(Dataset: TFDquery;
                   const cField: String; Tipo: TAggregateRetorne): currency;
 begin
 try
    with Dataset do
      begin
        AggregatesActive := False;
         if Aggregates.FindAggregate('Somar') = nil then
           with Aggregates.Add do
            begin
              Expression := 'Sum('+cField+')';
              Name := 'Somar';
              Active := True;
            end;
         if Aggregates.FindAggregate('Maxima') = nil then
            with Aggregates.Add do
             begin
               Expression := 'Max('+cField+')';
               name := 'Maxima';
               Active := True;
             end;
         if Aggregates.FindAggregate('Contar') = nil then
            with Aggregates.Add do
             begin
               Expression := 'Count('+cField+')';
               name := 'Contar';
               Active := True;
            end;
         if Aggregates.FindAggregate('Media') = nil then
            with Aggregates.Add do
             begin
               Expression := 'Avg('+cField+')';
               name := 'Media';
               Active := True;
            end;
         AggregatesActive := true;
          case Tipo of
            ftSomar:result:=Aggregates.FindAggregate('Somar').Value;
            ftMaxima:result:=Aggregates.FindAggregate('Maxima').Value;
            ftContar:result:= Aggregates.FindAggregate('Contar').Value;
            FtMedia:result:= Aggregates.FindAggregate('Media').Value;
          end;
       end;
 except
  on e:Exception do
    raise TypeAggregateERROR.Create(
                    'Erro na passagem de parâmetros'+sLineBreak+
                   'ou confira se o DataSet esta Ativo');//propagar a exceção

   end;
 end;

class function TOperacoes.Retornar(Dataset: TClientDataset; const cField: String; Tipo: TAggregateRetorne): currency;
 begin
 try
    with Dataset do
      begin
        AggregatesActive := False;
         if Aggregates.Find('Somar') = nil then
           with Aggregates.Add do
            begin
              Expression := 'Sum('+cField+')';
              AggregateName := 'Somar';
              Active := True;
            end;
         if Aggregates.Find('Maxima') = nil then
            with Aggregates.Add do
             begin
               Expression := 'Max('+cField+')';
               AggregateName := 'Maxima';
               Active := True;
             end;
         if Aggregates.Find('Contar') = nil then
            with Aggregates.Add do
             begin
               Expression := 'Count('+cField+')';
               AggregateName := 'Contar';
               Active := True;
            end;
         if Aggregates.Find('Media') = nil then
            with Aggregates.Add do
             begin
               Expression := 'Avg('+cField+')';
               AggregateName := 'Media';
               Active := True;
            end;
         AggregatesActive := true;
          case Tipo of
            ftSomar:result:=Aggregates.Find('Somar').Value;
            ftMaxima:result:=Aggregates.Find('Maxima').Value;
            ftContar:result:= Aggregates.Find('Contar').Value;
            FtMedia:result:= Aggregates.Find('Media').Value;
          end;
       end;
 except
  on e:Exception do
    raise TypeAggregateERROR.Create(
                    'Erro na passagem de parâmetros'+sLineBreak+
                   'ou confira se o DataSet esta Ativo');//propagar a exceção

   end;
end;

end.