You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '-50,50' at line 1syntax error: select id,ten as ten,tenkhongdau,type,thumb,photo,masp,gia,giakm,cpu,ram,diacung,manghinh,hdh,card,spmoi,spbanchay,id_danhmuc FROM table_product where  type='san-pham' and hienthi=1 order by gia limit -50,50