mysql - "Mixing of GROUP columns .. with no GROUP columns is illegal if there is no GROUP BY clause"

Question

我正在 Visual Studio 2012 上使用 C# 开发一个软件。我使用 MySQL Connector 6.9.1 进行 MySQL 连接。我的软件在我的操作系统(Win8 x64)上运行顺利，但在 Win7 上无法运行(在 VMWare 上，我必须在 Win7 上尝试一下)

这是抛出这个异常:

MySql.Data.MySqlClient.MySqlException (0x80004005): Mixing of GROUP columns (MIN(),MAX(),COUNT(),...) with no GROUP columns is illegal if there is no GROUP BY clause

这是我的代码:

      MySqlCommand komut = new MySqlCommand();
        komut.Connection = baglan;
        komut.CommandType = CommandType.Text;
        komut.CommandText = "SELECT count(*),yetki FROM kullanicilar WHERE kadi=@kadi AND sifre=@sifre";
        komut.Parameters.AddWithValue("@kadi", txtKadi.Text);
        komut.Parameters.AddWithValue("@sifre", txtSifre.Text);
        MySqlDataReader oku = komut.ExecuteReader();
        oku.Read();
        if (oku.GetInt32(0) > 0)
        {

            if (oku.GetString("yetki") == "0")
            {
                MessageBox.Show("Hesabınız aktif değil.","Hesap Deaktif",MessageBoxButtons.OK,MessageBoxIcon.Exclamation);
                baglan.Close();
                return;
            }

            RandevulariYonet randPenc = new RandevulariYonet(txtKadi.Text, this);
            this.Hide();
            randPenc.ShowDialog();

        }
        else
        {
            MessageBox.Show("Giriş Başarsız", "Giriş Başarısız", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);

        }

Answer 1

问题出在 SQL 语句中:

SELECT count(*),yetki 
FROM kullanicilar 
WHERE kadi=@kadi AND sifre=@sifre

您使用 count(*) 和另一列，而不对其进行分组。它应该看起来像这样:

SELECT count(*),yetki 
FROM kullanicilar 
WHERE kadi=@kadi AND sifre=@sifre 
GROUP BY yetki