Question

我正在尝试删除表上的最新条目，但我使用的SQL查询根本就不删除任何内容。我使用断点并多次读取代码，无法找到任何错误，有人能告诉我我做错了吗？

private void button1_Click(object sender, EventArgs e)
{
    string connectionString;
    var path = @"C:\Users\Administrator\Desktop\connstring.txt";
    using (StreamReader sr = new StreamReader(path))
    {
        connectionString = sr.ReadLine();
    }

    var connection = new SqlConnection(connectionString);

    MessageBox.Show("Um grupo de trabalhadores, está agora  a apagar os seus dados, aguarde.");

    string queryString = string.Empty;
    using (connection)
    {
        connection.Open();
        queryString = "DELETE FROM wgcdoccab WHERE numdoc IN (SELECT TOP 100 numdoc  FROM WGCDOCCAB   WHERE serie ='1' and tipodoc ='FSS' and contribuinte ='999999990' and  datadoc = CONVERT(varchar(10),dateadd(dd, -1, getdate()),120) ORDER BY numdoc DESC)";
        SqlCommand command = new SqlCommand(queryString, connection);

        command.Connection.Close();
    }

    MessageBox.Show("Apesar de cansados e sujos os trabalhadores mandam avisar que foi tudo apagado!");

Answer 1

您需要做的第一件事是在command上调用ExecuteNonQuery：

int deletionCount = command.ExexuteNonQuery();
Console.WriteLine("Deleted {0} items", deletionCount);

接下来，您需要确保命令本身已关闭，而不是其连接。连接由using语句关闭，因此您无需担心。

更改后代码应如下所示：

using (var connection = new SqlConnection(connectionString)) {
    connection.Open();
    MessageBox.Show("Um grupo de trabalhadores, está agora  a apagar os seus dados, aguarde.");
    string queryString = string.Empty;
    queryString = "DELETE FROM wgcdoccab WHERE numdoc IN (SELECT TOP 100 numdoc  FROM WGCDOCCAB   WHERE serie ='1' and tipodoc ='FSS' and contribuinte ='999999990' and  datadoc = CONVERT(varchar(10),dateadd(dd, -1, getdate()),120) ORDER BY numdoc DESC)";
    using (SqlCommand command = new SqlCommand(queryString, connection)) {
        int deletionCount = command.ExexuteNonQuery();
        MessageBox.Show("Deleted "+deletionCount+" items");
    }
}

如果表包含100个匹配的记录，则此代码应显示Deleted 100 items，如果表中的匹配记录少于100个，则显示已删除记录的实际数量。

SQL删除查询无效

1 个答案: