查询在HeidiSQL中有效但在C＃中失败

Question

下面的查询适用于HeidiSQL，但在尝试在C＃

中使用它时会出错

SELECT title.id,title.title,title.production_year,movie_info.info FROM title NATURAL JOIN movie_info WHERE title.id <= 1000;

它告诉我以下内容：

我使用以下代码检索MySqlDataReader对象：

public override MySqlDataReader Retrieve(string sql)
{
    MySqlCommand cmd = new MySqlCommand(sql, GetConnection());
    return cmd.ExecuteReader();
}

我从我的主要方法中调用它：

static void Main(string[] args)
{
    MySQLFacade facade = new MySQLFacade("127.0.0.1", "omitted", "omitted", "imdb");
    MySqlDataReader reader = facade.Retrieve(
        "SELECT title.id,title.title,title.production_year,movie_info.info" +
        "FROM title " +
        "NATURAL JOIN movie_info" +
        " WHERE title.id <= 1000;");
    using (reader)
    {
        while (reader.Read())
        {
            for (int i = 0; i < reader.FieldCount; i++)
            {
                Console.WriteLine(reader.GetValue(i));
            }
            Console.WriteLine();
        }
    }
    Console.ReadLine();
}

与数据库管理器相比，我是否可能遗漏了在C＃中使用格式化SQL字符串的内容？

Answer 1

FROM之前缺少一个空格：

MySqlDataReader reader = facade.Retrieve(
 "SELECT title.id,title.title,title.production_year,movie_info.info" + // <-- here
 "FROM title " +
 "NATURAL JOIN movie_info" +
 " WHERE title.id <= 1000;");

在你的回答中，你已将所有内容放入一行，并添加了缺失的空格。

Answer 2

使用@作为多行，最好使用参数来避免sql注入：

static void Main(string[] args)
{
    MySQLFacade facade = new MySQLFacade("127.0.0.1", "omitted", "omitted", "imdb");
    MySqlDataReader reader = facade.Retrieve(
        @"SELECT title.id,title.title,title.production_year,movie_info.info
        FROM title
        NATURAL JOIN movie_info
        WHERE title.id <= 1000");
    using (reader)
    {
        while (reader.Read())
        {
            for (int i = 0; i < reader.FieldCount; i++)
            {
                Console.WriteLine(reader.GetValue(i));
            }
            Console.WriteLine();
        }
    }
    Console.ReadLine();
}