请教jsp加sql语句的问题，先谢了

String t= request.getParameter("t");//从页面接到得值为：Cannon
String gser =request.getParameter("gser");//从页面接到得值为：sign


readcount=c.getGoodsCount("select count(*) from goods,detail where goods.id=detail.tid and '"+gser+"' like '%"+t+"%'");//就是这条语句的问题，我把'"+gser+"'换成sign就能得到readcount 的值。谁能告诉我为什么啊？？？？？？？？、
System.out.println(readcount);//但为什么得到的值是0啊。


getGoodsCount（）方法如下：
public int getGoodsCount(String sql){
  Connection conn=getConn();
  ResultSet rs=null;
  int i=0;
  try {
  PreparedStatement pst = conn.prepareStatement(sql);
  rs=pst.executeQuery();
  rs.next();
  i= rs.getInt(1);
  } catch (SQLException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
  }
  return i;
  }

------解决方案--------------------
readcount=c.getGoodsCount("select count(*) from goods,detail where goods.id=detail.tid and "+gser+" like '%"+t+"%'");
这样写试试
------解决方案--------------------
select count(*) from goods,detail where goods.id=detail.tid and "+gser+" like '%"+t+"%'

gser两边不要‘’你试试
------解决方案--------------------
表的字段不要加单引号