Question

我有以下代码C＃：

IMapper mapper = new Mapper(session);

//...

var names = new [] {"n1", "n2", "n3"};
//Generation of question marks   
var inStr = string.Join(",", names.Select(n=>"?"));
var users = mapper.Fetch<User>($"SELECT * FROM users WHERE name IN ({inStr})", names);

这种方法有效。但也许有人知道一个更优雅的解决方案？

Answer 1

要在单个参数中提供动态值列表，请使用IN运算符，后跟查询中没有括号的问号占位符。

例如：

var names = new [] {"n1", "n2", "n3"};
var users = mapper.Fetch<User>("SELECT * FROM users WHERE name IN ?", names);

DataStax Cassandra C＃驱动程序：WHERE IN（？）查询带有collection参数

1 个答案: