private void button3_Click(object sender, EventArgs e)
{
DBConnect();
oledbCon.Open();
string cmdstr = @"select count(*) from 学生基本信息 where 年龄 = '" +this.textBox1.Text+ "'";
OleDbCommand cmd = new OleDbCommand(cmdstr, oledbCon);
OleDbDataReader reader = cmd.ExecuteReader();
if (reader.HasRows)
{
reader.Read();
int count = reader.GetInt32(0);
richTextBox1.Text = "该年龄的人数为 " + count +"人";
}
}