function getjsontoWhereSql(const ajsonarray: TJSONArray): string;
var
  i: Integer;
  ajsonobject: TJSONObject;
  afieldname,afieldvalue:string;
  sqlwherestring:string;
  afieldoperator:string;
begin
  sqlwherestring := ‘ ‘;
  for i := 0 to ajsonarray.Size - 1 do
  begin
    ajsonobject := ajsonarray.Get(i) as TJSONObject;
    afieldname := ajsonobject.Pairs[0].JsonString.ToString;
    afieldname := ReplaceStr(afieldname, ‘"‘, ‘‘);
    afieldvalue := ajsonobject.Pairs[0].JsonValue.Value;
    afieldoperator := ajsonobject.Pairs[1].JsonValue.Value;
    sqlwherestring := sqlwherestring + ‘ ‘ + afieldname + ‘ ‘ + afieldoperator +
      ‘ ‘ + QuotedStr(afieldvalue) + ‘ and ‘;
  end;
  Result := ‘ where ‘ + LeftStr(sqlwherestring,
    Length(sqlwherestring) - 5);
end;

///////////////

function getjsontoInsertSql(const ajsonarray:TJSONArray; tablename: string): string;
var
  i,j: Integer;
  ajsonobject: TJSONObject;
  sqlstring:string;
  afieldname,afieldvalue:string;
begin
  sqlstring := ‘‘;
  for i := 0 to ajsonarray.Size - 1 do
  begin
    sqlstring := sqlstring + ‘ insert into ‘ + tablename + ‘(‘;
    ajsonobject := ajsonarray.Get(i) as TJSONObject;
    for j := 0 to ajsonobject.Size - 1 do
    begin
      afieldname := ajsonobject.Pairs[j].JsonString.ToString;
      sqlstring := sqlstring + ReplaceStr(afieldname, ‘"‘, ‘‘) + ‘,‘;
    end;
    sqlstring := LeftStr(sqlstring, Length(sqlstring) - 1);
    sqlstring := sqlstring + ‘)values(‘;
    for j := 0 to ajsonobject.Size - 1 do
    begin
      afieldvalue := ajsonobject.Pairs[j].JsonValue.Value;
      sqlstring := sqlstring + QuotedStr(afieldvalue) + ‘,‘;
    end;
    sqlstring := LeftStr(sqlstring, Length(sqlstring) - 1);
    sqlstring := sqlstring + ‘)‘;
  end;
  Result := sqlstring;
end;

///////////

function TForm1.getjsontoSelectSql(const ajsonwherearray: TJSONArray;
  tablename: string;const theSql:string): string;
var
  sqlwherestring:string;
begin
  sqlwherestring := getjsontoWhereSql(ajsonwherearray);
  result := thesql + ‘ from ‘ +  tablename + sqlwherestring;
end;

/////////

function getjsontoUpdadteSql(const ajsonUpdatearray,ajsonWherearray: TJSONArray;
  tablename: string): string;
var
  i,j: Integer;
  ajsonobject: TJSONObject;
  sqlstring:string;
  afieldname,afieldvalue:string;
  setvaluesql,sqlwherestring:string;
  afieldoperator:string;
begin
  sqlstring := ‘‘;
  for i := 0 to ajsonUpdatearray.Size - 1 do
  begin
    sqlstring := sqlstring + ‘ update ‘ + tablename + ‘ set ‘;
    ajsonobject := ajsonUpdatearray.Get(i) as TJSONObject;
    setvaluesql := ‘‘;
    for j := 0 to ajsonobject.Size - 1 do
    begin
      afieldname := ajsonobject.Pairs[j].JsonString.ToString;
      afieldname := ReplaceStr(afieldname, ‘"‘, ‘‘);
      afieldvalue := ajsonobject.Pairs[j].JsonValue.Value;
      setvaluesql := setvaluesql + afieldname + ‘ = ‘ + QuotedStr(afieldvalue) + ‘,‘;
    end;
    setvaluesql := LeftStr(setvaluesql, Length(setvaluesql) - 1);
    //////
    sqlwherestring := getjsontoWhereSql(ajsonWherearray);
    sqlstring := sqlstring + setvaluesql + sqlwherestring;
  end;
  Result := sqlstring;
end;

////////////////

function getjsontoDeleteSql(const ajsonWherearray: TJSONArray; tablename: string): string;
var
  i: Integer;
  ajsonobject: TJSONObject;
  sqlstring:string;
  afieldname,afieldvalue:string;
  sqlwherestring:string;
  afieldoperator:string;
begin
  sqlwherestring := ‘ ‘;
  for i := 0 to ajsonWherearray.Size - 1 do
  begin
    ajsonobject := ajsonWherearray.Get(i) as TJSONObject;
    afieldname := ajsonobject.Pairs[0].JsonString.ToString;
    afieldname := ReplaceStr(afieldname, ‘"‘, ‘‘);
    afieldvalue := ajsonobject.Pairs[0].JsonValue.Value;
    afieldoperator := ajsonobject.Pairs[1].JsonValue.Value;
    sqlwherestring := sqlwherestring + ‘ ‘ + afieldname + ‘ ‘ + afieldoperator +
      ‘ ‘ + QuotedStr(afieldvalue) + ‘ and ‘;
  end;
  sqlwherestring := ‘ where ‘ + LeftStr(sqlwherestring,Length(sqlwherestring) - 5);
  sqlstring := ‘ delete from ‘ + tablename + sqlwherestring;
  Result := sqlstring;
end;

////////生成Jsonarray

procedure TForm1.Button1Click(Sender: TObject);
var
  i: Integer;
  JSONCars: TJSONArray;
  Car, Price: TJSONObject;
begin
  JSONCars := TJSONArray.Create;
  try
    for i := low(Cars) to high(Cars) do
    begin
      Car := TJSONObject.Create;
      JSONCars.AddElement(Car);
      Car.AddPair(‘manufacturer‘, Cars[i][TCarInfo.Manufacturer]);
      Car.AddPair(‘name‘, Cars[i][TCarInfo.Name]);
      Price := TJSONObject.Create;
      Car.AddPair(‘price‘, Cars[i][TCarInfo.Name]);
    //  Price.AddPair(‘value‘, TJSONNumber.Create(Cars[i][TCarInfo.Price].ToInteger));
     // Price.AddPair(‘currency‘, Cars[i][TCarInfo.Currency]);
    end;
    JSON := JSONCars.ToString;
    memo3.Text := json;
  finally
    JSONCars.Free;
  end;
end;

本文出自 “一切有为法，如梦幻泡影” 博客，请务必保留此出处http://kaixinbuliao.blog.51cto.com/2567365/1611083

利用Jsonarray拼接sql