小编Jer*_*unx的帖子

你好,我正试图在没有匹配的学生时犯错......它会显示如下这个 No matching records found,我希望列名仍然相同,但仍然没有把它搞清楚......有人可以告诉我这是不是对？？

继承我的功能......我在那里添加评论我把错误...但我不知道如何获得列名

public void SearchTableStudent() {
        String tempSearchValue = searchStudent.getText().trim();
        boolean empty = true;
        sql = "SELECT student_id as 'Student ID',"
                + "concat(lastname, '  ,  ', firstname, ' ', middlename) as 'Name'"
                + "FROM user "
                + "WHERE CAST(student_id as CHAR) LIKE '%" + tempSearchValue + "%'";
        try {
            pst = conn.prepareStatement(sql);
            rs = pst.executeQuery();
            while(rs.next()) {
                table.setModel(DbUtils.resultSetToTableModel(rs));
                empty = false;
            }
            if(empty) {
                String error = "";
                table.setModel(new javax.swing.table.DefaultTableModel(
                    new Object [][] {
                        {"No …

我试图在我的另一个表上添加外键但这给了我错误 #1072 - Key column 'role_id' doesn't exist in table

你好我已经创建了一个名为的表 role

然后我就是这样创造的

create table role (
  role_id varchar(15)
  primary key (role_id)
)

然后当我试图改变我user桌子上的桌子时

alter table user
add foreign key (role_id)
references role(role_id)

我收到了这样的错误

#1072 - Key column 'role_id' doesn't exist in table

对不起是菜鸟..

我用这样d.PODate.ToString()来显示(见图)我可以使用inspect元素看到它...我想只显示日期而不是时间,当我尝试使用d.PODate.ToString("d")它时给了我这样的错误Method 'System.String ToString(System.String)' has no supported translation to SQL 并且同样d.PODate.ToShortDateString()得到这样的错误Method 'System.String ToShortDateString()' has no supported translation to SQL.

编辑

这是我的GET方法

[HttpGet]
public Models.SysDataTablePager Get()
{
    NameValueCollection nvc = HttpUtility.ParseQueryString(Request.RequestUri.Query);

    string sEcho = nvc["sEcho"].ToString();
    int iDisplayStart = Convert.ToInt32(nvc["iDisplayStart"]);
    string sSearch = nvc["sSearch"].ToString();
    int iSortCol = Convert.ToInt32(nvc["iSortCol_0"]);
    string sSortDir = nvc["sSortDir_0"].ToString();

    var BranchId = Convert.ToInt32(((wfmis.Global)HttpContext.Current.ApplicationInstance).CurrentBranchId);

    var Count = db.TrnPurchaseOrders.Where(d => d.MstUser.Id == secure.GetCurrentUser() && 
    d.MstBranch.Id == BranchId).Count();

    var PurchaseOrders = from d in db.TrnPurchaseOrders …