这只是sql的问题呀,
SqlDataReader reader1 = sqlfunction.SqlReader("select id from A where id='2004' ");//sqlfunction.SqlReader为数据库读取方法
if(reader1.Reader())
{
reader1 = sqlfunction.SqlReader("select id from B where AID="+reader1["id"].Tostring());
if(reader1.Reader())
{
//接下去写
}
}