是否可以在 Where 子句之外的其他地方使用 OleDBCommand 参数？

Question

我有这个代码：

using (OleDbCommand cmd = conn.CreateCommand())
{
    cmd.CommandText = string.Format(
        @"SELECT TOP {0} t_accounts.account_no as AccountID, IIF(ISNULL(t_accounts.name),'[blank]',t_accounts.name) AS Name 
        FROM t_accounts 
        INNER JOIN td_department_accounts ON (t_accounts.account_no = td_department_accounts.account_no) 
        WHERE (AccountID >= @firstId) AND type = 'DE'", CountToFetch);
    cmd.CommandType = CommandType.Text;
    cmd.Parameters.AddWithValue("@firstId", FirstId);

...但想知道我是否也可以使用参数作为最高计数，例如：

using (OleDbCommand cmd = conn.CreateCommand())
{
    cmd.CommandText = 
        @"SELECT TOP @count t_accounts.account_no as AccountID, IIF(ISNULL(t_accounts.name),'[blank]',t_accounts.name) AS Name 
        FROM t_accounts 
        INNER JOIN td_department_accounts ON (t_accounts.account_no = td_department_accounts.account_no) 
        WHERE (AccountID >= @firstId) AND type = 'DE'";
    cmd.CommandType = CommandType.Text;
    cmd.Parameters.AddWithValue("@firstId", FirstId);
    cmd.Parameters.AddWithValue("@count", CountToFetch);

...或者数据库参数是否仅限于 WHERE 子句？

更新

使用此代码：

  cmd.CommandText = 
        @"SELECT TOP @countToFetch t_accounts.account_no as AccountID, 
    IIF(ISNULL(t_accounts.name),'[blank]',t_accounts.name) AS Name 
        FROM t_accounts 
        INNER JOIN td_department_accounts ON (t_accounts.account_no = 
    td_department_accounts.account_no) 
        WHERE (AccountID >= @firstId) AND type = 'DE'";
    . . .
  cmd.Parameters.AddWithValue("@firstId", FirstId);
  cmd.Parameters.AddWithValue("@countToFetch", CountToFetch);

...我知道了，“SELECT 语句包含一个保留字或参数名称拼写错误或缺失，或者标点符号不正确。”

所以我又回到了：

   cmd.CommandText = string.Format(
        @"SELECT TOP {0} t_accounts.account_no as AccountID, 
    IIF(ISNULL(t_accounts.name),'[blank]',t_accounts.name) AS Name 
        FROM t_accounts 
        INNER JOIN td_department_accounts ON (t_accounts.account_no = 
    td_department_accounts.account_no) 
        WHERE (AccountID >= @firstId) AND type = 'DE'", CountToFetch);
    . . .
    cmd.Parameters.AddWithValue("@firstId", FirstId);

更新 2

这个：

SELECT TOP (@countToFetch) t_accounts.account_no as AccountID, IIF(ISNULL
(t_accounts.name),'[blank]',t_accounts.name) AS Name 
FROM t_accounts 
INNER JOIN td_department_accounts ON (t_accounts.account_no = td_department_accounts.account_no) 
WHERE (AccountID >= @firstId) AND type = 'DE'"

...在 Access 中告诉我“SELECT 语句包含拼写错误或丢失的保留字或参数名称，或者标点符号不正确。”

注意：邮递员在进行 REST 调用时告诉我完全相同的事情，最终导致进行该查询。

更新 3

我也像在更新 2 中一样尝试过，但使用“：”而不是“@”，这样：

SELECT TOP (?) t_accounts.account_no as AccountID, IIF(ISNULL(t_accounts.name),'[blank]',t_accounts.name) AS Name 
FROM t_accounts 
INNER JOIN td_department_accounts ON (t_accounts.account_no = td_department_accounts.account_no) 
WHERE (AccountID >= ?) AND type = 'DE'"

Answer 1

我看到this 的帖子似乎表明这个确实工作，至少在 T-SQL 中是这样。鉴于此，我倾向于假设它适用于 Access。就像上面所说的，记住要包含括号。

无论如何，参数只能在WHERE 子句中是绝对不正确的。您可以在SELECT 甚至ORDER BY 中使用它们。