Question

我一直在尝试从表中删除行但是我编写的代码不起作用，我不确定它是SQL语法还是代码本身，visual studio不是抛出任何错误它只是启动程序没有任何麻烦，我点击按钮删除后，程序冻结，我甚至无法关闭它。如果我在执行此操作后检查数据库，则保持不变。

对不起，如果我不能解释得很好，英语不是我的母语，所以对我来说有点难，请提前谢谢。

      private void button1_Click(object sender, EventArgs e)
    {
        MessageBox.Show("DOING STUFF");
        bool check = true;
        do
        {
            string connectionString = @"Data Source=.\wintouch;Initial Catalog=bbl;User ID=sa;Password=Pa$$w0rd";
            string queryString = string.Empty;
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                connection.Open();
                queryString = "DELETE FROM wgcdoccab WHERE serie ='1' tipodoc ='FSS' AND and contribuinte ='999999990' and  datadoc = CONVERT(varchar(10),(dateadd(dd, -2, getdate())),120) ";                    
                SqlCommand command = new SqlCommand(queryString, connection);
                //command.Connection.Open();
                command.ExecuteNonQuery();

            }
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                connection.Open();
                queryString = "SELECT * FROM wgcdoccab WHERE serie ='1' tipodoc ='FSS' AND and contribuinte ='999999990' and  datadoc = CONVERT(varchar(10),(dateadd(dd, -2, getdate())),120) ";

                using (SqlCommand command = new SqlCommand(queryString, connection))
                using (SqlDataReader reader = command.ExecuteReader())
                {
                    if (reader.HasRows)
                    {
                        check = true;
                    }
                    else
                    {
                        check = false;
                        MessageBox.Show("STILL DOING STUFF");
                    }
                    command.Connection.Close();
                }
            }
        }
        while (check);

Answer 1

DELETE和SELECT的内联查询不正确。更正的查询将如下所示。

删除查询

DELETE FROM wgcdoccab WHERE serie ='1' AND tipodoc ='FSS' AND contribuinte ='999999990' 
 and  datadoc = CONVERT(varchar(10),(dateadd(dd, -2, getdate())),120)

选择查询

SELECT * FROM wgcdoccab WHERE serie ='1' AND tipodoc ='FSS' AND    contribuinte ='999999990' 
and  datadoc = CONVERT(varchar(10),(dateadd(dd, -2, getdate())),120)

Answer 2

我不确定您认为SQL命令如何工作，但它们肯定不是异步的，因此您既不需要循环也不需要第二个using块来检查您刚刚删除的行是否仍然存在。只有在删除所有行后，删除过程才会结束。

您发布的代码也不是真正的代码，因为您的WHERE子句中的语法无效，您应该收到SQL异常。

所以你的代码可以缩短为以下内容（修复WHERE子句）：

private void button1_Click(object sender, EventArgs e)
{
    MessageBox.Show("DOING STUFF");

        string connectionString = @"Data Source=.\wintouch;Initial Catalog=bbl;User ID=sa;Password=Pa$$w0rd";
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            connection.Open();

            string queryString = "DELETE FROM wgcdoccab WHERE serie ='1' tipodoc ='FSS' AND and contribuinte ='999999990' and  datadoc = CONVERT(varchar(10),(dateadd(dd, -2, getdate())),120) ";                    
            SqlCommand command = new SqlCommand(queryString, connection);
            command.ExecuteNonQuery();
        }
}

删除查询而不是调用SQL c＃

2 个答案: