Question

我有以下INSERT：

 public static void insertStudent(int personId, string firstName, string lastName, string DOB, int phoneNumber, string address, int postCode, string majorField, int gradePointAverage)
        {
            MySqlConnection conn;
            MySqlCommand cmd;
            string sql = "INSERT INTO person (personId, firstName, lastName, DOB, phoneNumber, address, postCode) VALUES (@personId, @firstName, @lastName, @DOB, @phoneNumber, @address, @postCode)";
            GetConnection(out conn, out cmd, sql);
            try
            {
                cmd.Parameters.AddWithValue("@personId", personId);
                cmd.Parameters.AddWithValue("@firstName", firstName);
                cmd.Parameters.AddWithValue("@lastName", lastName);
                cmd.Parameters.AddWithValue("@DOB", DOB);
                cmd.Parameters.AddWithValue("@phoneNumber", phoneNumber);
                cmd.Parameters.AddWithValue("@address", address);
                cmd.Parameters.AddWithValue("@postCode", postCode);
                cmd.ExecuteNonQuery();

                long id = (long)cmd.LastInsertedId;

                sql = "INSERT INTO student (Person_PersonId, majorField , gradePointAverage) VALUES (" + id + ",@majorField, @gradePointAverage";
                cmd = new MySqlCommand(sql, conn);
                cmd.Parameters.AddWithValue("@majorField", majorField);
                cmd.Parameters.AddWithValue("@gradePointAverage", gradePointAverage);
                cmd.ExecuteNonQuery();
            }

            catch (NullReferenceException nre)
            {
                MessageBox.Show(nre.Message);
            }
            catch (Exception e)
            {
                MessageBox.Show(e.Message);
            }
            finally
            {
                try
                {
                    MessageBox.Show("New student record created created.");
                    cmd.Connection.Close();
                    conn.Close();
                }
                catch (Exception e)
                {
                    MessageBox.Show(e.Message);
                }
            }
        }

由此按钮执行：

 private void btnInsertStudentNumberAdmin_Click(object sender, EventArgs e)
    {
        StudentHelperClass.insertStudent(int.Parse(txtPersonIDStudent.Text), txtFirstNameStudent.Text, txtLastNameStudent.Text, txtDOBStudent.Text, int.Parse(txtPhoneNumberStudent.Text), txtAddressStudent.Text, int.Parse(txtPostCodeStudent.Text), txtMajorFieldStudent.Text, int.Parse(txtGpaStudent.Text));
    }

但是点击后，我会看到一个消息框，显示you have an error in your SQL syntax; check the manual that corresponds to your mySql server version for the right version for the right syntax to use near " at line 1，然后插入person表的条目，但学生的条目不会插入。

我确保所有int都是int，所有strings都是字符串。我不确定是什么问题。

Answer 1

sql = "INSERT INTO student (
    Person_PersonId, 
    majorField,
    gradePointAverage
) VALUES (" + id + ",
    @majorField, 
    @gradePointAverage";

缺少一个近括号。它应该是：

sql = "INSERT INTO student (
    Person_PersonId, 
    majorField,
    gradePointAverage
) VALUES (" + id + ",
    @majorField, 
    @gradePointAverage
)";

Answer 2

sql =“INSERT INTO student（Person_PersonId，majorField，gradePointAverage）VALUES（”+ id +“，@ majorField，@gradePointAverage）”; 错过了结局）......？

为什么我的INSERT语句不适用于一个表？

2 个答案: