缺少运算符语法

Question

在对访问数据库执行此查询时，我收到了缺少的运算符语法错误。它在我使用SQL服务器时有效。任何帮助表示赞赏：

String sql = "Select tblStudent.StudentID,tblStudent.studentFirstName,tblStudent.studentLastName,tblSchool.schoolName,tblAgents.agentFirstName,tblAgents.agentLastName,tblAgents.agentID,tblGuardians.guardianFirstName,tblGuardians.guardianLastName,tblGuardians.guardianID,tblConsultants.consultantFirstName,tblConsultants.consultantLastName,tblConsultants.consultantID " +
        "FROM (tblStudent LEFT JOIN tblSchool " +
        "ON (tblStudent.schoolID = tblSchool.schoolID)) " +
        "LEFT JOIN tblAgents " +
        "ON (tblStudent.agentID = tblAgents.agentID) " +
         "LEFT JOIN tblGuardians " +
        "ON (tblStudent.guardianID = tblGuardians.guardianID) " +
         "LEFT JOIN tblConsultants " +
        "ON (tblStudent.consultantID = tblConsultants.consultantID) " +
        "WHERE tblStudent.StudentID=@studentID";

        m_dbConnection.Open();
        using (OleDbCommand cmd = new OleDbCommand(sql, m_dbConnection))
        {
            cmd.Parameters.AddWithValue("@StudentID", studentID);
            using (OleDbDataReader dr = cmd.ExecuteReader())
            {
                while (dr.Read())
                {

                      lblSchool.Text = Convert.ToString(dr["schoolName"]);
                      lblStudentFirstName.Text = Convert.ToString(dr["studentFirstName"]);
                      lblStudentLastName.Text = Convert.ToString(dr["studentLastName"]);
                      lblAgentFirstName.Text = Convert.ToString(dr["agentFirstName"]);
                      lblAgentLastName.Text = Convert.ToString(dr["agentLastName"]);
                      lblAgentID.Text = Convert.ToString(dr["agentID"]);
                      lblGuardianFirstName.Text = Convert.ToString(dr["guardianFirstName"]);
                      lblGuardianLastName.Text = Convert.ToString(dr["guardianLastName"]);
                      lblGuardianID.Text = Convert.ToString(dr["guardianID"]);
                      lblConsultantFirstName.Text = Convert.ToString(dr["consultantFirstName"]);
                      lblConsultantLastName.Text = Convert.ToString(dr["consultantLastName"]);
                      lblConsultantID.Text = Convert.ToString(dr["consultantID"]);
                      lblID.Text = studentID;   

但如果我这样做：它有效：

String sql2 = "Select tblStudent.StudentID,tblStudent.studentFirstName,tblStudent.studentLastName,tblSchool.schoolName,tblAgents.agentFirstName,tblAgents.agentLastName,tblAgents.agentID " +
        "FROM (tblStudent LEFT JOIN tblSchool " +
        "ON (tblStudent.schoolID = tblSchool.schoolID)) " +
        "LEFT JOIN tblAgents " +
        "ON (tblStudent.agentID = tblAgents.agentID) " +
        "WHERE tblStudent.StudentID=@studentID";

答案是这样的。我不得不使用多个括号

  String sql = "Select tblStudent.StudentID,tblStudent.studentFirstName,tblStudent.studentLastName,tblSchool.schoolName,tblAgents.agentFirstName,tblAgents.agentLastName,tblAgents.agentID,tblGuardians.guardianFirstName,tblGuardians.guardianLastName,tblGuardians.guardianID,tblConsultants.consultantFirstName,tblConsultants.consultantLastName,tblConsultants.consultantID " +
        "FROM ((((tblStudent LEFT JOIN tblSchool " +
        "ON tblStudent.schoolID = tblSchool.schoolID) " +
        "LEFT JOIN tblAgents " +
        "ON tblStudent.agentID = tblAgents.agentID) " +
        "LEFT JOIN tblGuardians " +
        "ON tblStudent.guardianID = tblGuardians.guardianID) " +
        "LEFT JOIN tblConsultants " +
        "ON tblStudent.consultantID = tblConsultants.consultantID) " +
        "WHERE tblStudent.StudentID=@studentID";