Question

这是我的代码：

(from customer in db.tblCustomers
  join product in db.tblProducts on customer.product_id equals product.id into str
  from prod in str.DefaultIfEmpty()
  where customer.code.Substring(SqlFunctions.PatIndex("%[^0]%", customer.code).Value - 1) == customerCode
  select prod.name).SingleOrDefault();

如您所见，我使用PatIndex左修剪字符串，但我也想右修剪零。我该怎么办？

例如，如果customerCode为'123'，并且在db中，如果我有一个值为'001230000'的客户代码，则表示匹配。

Answer 1

验证CustomerCode之后的字符全为零：

(from customer in db.tblCustomers
  join product in db.tblProducts on customer.product_id equals product.id into str
  from prod in str.DefaultIfEmpty()
  let tail = customer.code.Substring(customer.code.IndexOf(customerCode)+customerCode.Length)
  where customer.code.Substring(SqlFunctions.PatIndex("%[^0]%", customer.code).Value - 1) == customerCode &&
        tail == new String('0', tail.Length)
  select prod.name).SingleOrDefault();

Answer 2

代替使用SqlFunctions.PatIndex。您可以使用string的TrimStart（）和TrimEnd（）方法。

例如

(from customer in db.tblCustomers
         join product in db.tblProducts on customer.product_id equals product.id into str
         from prod in str.DefaultIfEmpty()
         where customer.code.Contains(customerCode.TrimStart(new Char[] { '0' }).TrimEnd(new Char[] { '0' }))
         select prod.name).SingleOrDefault();

在C＃中使用SqlFunctions修剪字符

2 个答案: