[英]c# MySqlCommand.Parameters.AddWithValue, parameters to express a table, resulted command have a single quote added
我的問題是,當我使用AddWithValue時,命令中會出現兩個不需要的單引號。 這就是我所謂的函數:
string sqlTableName = "the_table_i_want";
DataTable myDataTable = SQLcom.SelectLastValueInTab(sqlTableName);
我的功能;
public static DataTable SelectLastValueInTab(string TableName)
{
using (MySqlConnection con = new MySqlConnection(ConnStr))
{
using (MySqlCommand myCommand = new MySqlCommand("SELECT * FROM @TabName ORDER BY id DESC LIMIT 1", con))
{
myCommand.Parameters.AddWithValue("@TabName", TableName);
try
{
con.Open();
MySqlDataReader testreader = myCommand.ExecuteReader();
結果命令為:
"SELECT * FROM 'the_table_i_want' ORDER BY id DESC LIMIT 1"
並且假設是:
"SELECT * FROM the_table_i_want ORDER BY id DESC LIMIT 1"
它導致程序崩潰,因為我有:
a syntax error near ''the_table_i_want' ORDER BY id DESC LIMIT 1'
PS:如果我不使用AddWithValuechange和更改
@TabName for the_table_i_want
在MySqlCommand中,它可以完美運行!
非常感謝 !
丹尼爾·GB
如注釋所建議,您不能使用參數來表示表或字段名稱。 另一種方法是將表名附加到查詢中。
public static DataTable SelectLastValueInTab(string TableName)
{
using (MySqlConnection con = new MySqlConnection(ConnStr))
{
string qry = "SELECT * FROM " + TableName + " ORDER BY id DESC LIMIT 1";
using (MySqlCommand myCommand = new MySqlCommand(qry, con))
{
try
{
con.Open();
MySqlDataReader testreader = myCommand.ExecuteReader();
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