c# 如何求出符合条件的总条数

一种使用select * from 数据库名然后用ds.tables[0].rows.count;

另一种 用 select count(*) from 数据库名 新建commmand对象cmd

用cmd.ExecuteScalar().ToString() 读出.代码如下

string connectionstr = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D://OlineExam//App_Data//db1.mdb;Persist Security Info=True";
OleDbConnection connection = new OleDbConnection(connectionstr);//新建连接
connection.Open();//打开连接
string str = "select count(*) from judequestion";
string acount ;
//OleDbDataAdapter da = new OleDbDataAdapter(str, connection);
//DataSet ds = new DataSet();
//da.Fill(ds);
//acount = ds.Tables[0].Rows.Count;
OleDbCommand cmd = new OleDbCommand(str, connection);

acount = cmd.ExecuteScalar().ToString() ;
Console.WriteLine(acount);
Console .ReadLine ();