我一直在尝试根据限制数量逐行删除几行,我试图只删除最新的条目但是,我想出的解决方案不断崩溃 VSHOST,有没有更好的方法来实现结果一样吗?
private void button1_Click(object sender, EventArgs e)
{
MessageBox.Show("A apagar dados...");
bool check = true;
do
{
string connectionString;
var path = @"C:\Users\Administrator\Desktop\connstring.txt";
using (StreamReader sr = new StreamReader(path))
{
connectionString = sr.ReadLine();
}
var connection = new SqlConnection(connectionString);
string queryString = string.Empty;
using (SqlConnection deleteconnection = new SqlConnection(connectionString))
{
deleteconnection.Open();
connection.Open();
queryString = "DELETE FROM wgcdoccab WHERE numdoc = (SELECT MAX(numdoc) FROM WGCDOCCAB WHERE serie ='1' and tipodoc ='FSS' and contribuinte ='999999990' and datadoc = CONVERT(varchar(10),dateadd(dd, -1, getdate()),120))";
SqlCommand command = new SqlCommand(queryString, connection);
command.ExecuteNonQuery();
connection.Close();
}
using (SqlConnection deleteconnection = new SqlConnection(connectionString))
{
connection.Open();
deleteconnection.Open();
queryString = "SELECT max(numdoc) FROM wgcdoccab WHERE serie ='1' and tipodoc ='FSS' and contribuinte ='999999990' and datadoc = CONVERT(varchar(10),(dateadd(dd, -1, getdate())), 120))";
using (SqlCommand command = new SqlCommand(queryString, connection))
using (SqlDataReader reader = command.ExecuteReader())
{
if (reader.HasRows)
{
check = true;
}
else
{
check = false;
MessageBox.Show("Dados Apagados com sucesso");
}
command.Connection.Close();
}
}
}
while (check);
代码相对简单,在 do-while 结束后,它变成了无尽的 cicle,因为它总是为 numdoc 返回 NULL 值,我似乎找不到绕过它的方法。 有什么建议吗?
最佳答案
我不明白循环的必要性。为什么不一次删除所有记录?
DELETE FROM wgcdoccab
WHERE
serie ='1' and
tipodoc ='FSS' and
contribuinte ='999999990' and
datadoc = CONVERT(varchar(10),dateadd(dd, -1, getdate()),120))";
如果您在循环中重复查询,它无论如何都会删除所有这些记录,而不仅仅是最后的记录。
“最后的”到底是什么意思?最后 2 个是最后 100 个吗?你必须给出“最后一个”的准确定义!
假设您要删除最后 10 个。你可以用这个查询来实现它(假设是 T-SQL):
DELETE FROM wgcdoccab
WHERE numdoc IN (
SELECT TOP 10 numdoc
FROM WGCDOCCAB
WHERE blahh blahh blahh
ODER BY numdoc DESC
)
关于c# - 什么是循环删除查询的最佳方式,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/31906115/