当需要向数据库插入空值时，sql语句的判断

 1  public int Update(AccountInfo account)
 2 {
 3     StringBuilder str1=new StringBuilder();
       StringBuilder str2=new StringBuilder();

 4    // int
 5    if( account.number!=0)
 6       {
 7          str1.Append("Number="+account.number",")
 8       }else
 9         {
10             str1.Append(" Number=null , ");
11         }
12 
13     //string
14     if(account.Name!=null&&account.Name!="")
15      {
16          str1.Append("Name=' " + account.Name+ " ' ,");
17       }else
18      {
19          str1.Append(" Name=' ' , ");
20      }

          str2.Append(" update table  set ");
          str2.Append(str1.ToString().Remove(str1.Length-1));
          str2.Append(" where ID="+ Account.ID+"");
          return SqlHelper.ExecuteSql(str2.ToString);
21 
22 
23 
24 }