Question

鉴于conn是OdbcConnection个对象且count是int，我如何将count作为参数用于查询？

...
var query = conn.CreateCommand();
query.CommandText = "select top ? * from players order by Points desc";
query.Parameters.Add("top", OdbcType.Int).Value = count;

var reader = query.ExecuteReader();
while (reader.Read())
{
    ...
}
...

这样我收到语法错误ERROR [42000] [Microsoft][ODBC SQL Server Driver][SQL Server]Incorrect syntax near '@P1'.

如果不可能的话，我会尝试以正确的方式做到这一点吗？

Answer 1

你可以这样做：

query.CommandText = "select top (@topparameter) * from players order by Points desc";
query.Parameters.AddWithValue("@topparameter", count.ToString());

如果您使用SqlServer，请使用SqlConnection和SqlCommand，如：

using (SqlConnection conn = new SqlConnection("YourConnectionString"))
{
    using (SqlCommand query = new SqlCommand("select top (@topparameter) * from players order by Points desc", conn))
    {
        query.Parameters.AddWithValue("@topparameter", count.ToString());
        var reader = query.ExecuteReader();
        while (reader.Read())
        {
        }
    }
}

Answer 2

您还可以使用SET ROWCOUNT，其优点是可以使用整数作为参数并避免动态查询。

SET ROWCOUNT @top;

select * from table;

SET ROWCOUNT 0;

阅读documentation

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