1. DB db_1 = new DB();
string sql = "select*from TB_SHANGPIN where SPDW ='袋'";
dataGridView2.DataSource = db_1.select_5(sql);
这个执行出来没数据




2. DB db_1 = new DB();
string sql = "select*from TB_SHANGPIN where SPBH =123456";
dataGridView2.DataSource = db_1.select_5(sql);
这个执行有数据,但是SPBH是主键