Question

我正在尝试使用PHP访问MySQL数据库。我需要从我的actor_id表中检索6个值，在html表中显示它们。我的SELECT语句是：

SELECT actor_id.actor_name, FROM actor_id WHERE movie.star1 = actor_id.actor_id;

现在我该如何添加另一部电影.star2，movie.star3等？

数据库结构

NAME - 字段电影 - movie_id title star1 star2 actor_id - actor_id actor_name

Answer 1

从这看起来，你实际上在这里使用两个表。但是，您的查询仅引用其中一个。

我认为你需要这样的东西：

SELECT 
    actor_id.actor_name, 
FROM 
    actor_id 
        join movie
            on movie.star1 = actor_id.actor_id
            or movie.star2 = actor_id.actor_id
            or movie.star3 = actor_id.actor_id
            -- etc etc

尽管如此，你可能会很好地read this lengthy Q&A that I wrote来更详细地解释这些事情。

Answer 2

正如我在评论中所说，这很容易（如果你read the manual）：

SELECT field1, field2, field3 AS altName, lastFieldNoCommaHere
    FROM table
WHERE someField = 'value'
  AND id IN (1,2,3,4,5,6,7,8,9)
  AND (dateField > NOW()
       OR dateField IS NULL);

RTM并且不使用mysql_*扩展名，它已被弃用。使用PDO或mysqli_*，不仅仅是因为弃用问题，But for various reasons。

当您在where子句中使用movie.star1时，您应该同时查看the JOIN syntax：

SELECT actor_id.name 
FROM actor_id
    LEFT JOIN movie
       ON movie.star1 = actor_id.actor_id
WHERE actor_id.actor_id IN (1,2,4,5,6,7,8,123);

这可能是你所追求的，或许是：

SELECT actor_id.name
FROM actor_id
WHERE actor_id.actor_id
          IN ( SELECT movie.star1
                  FROM movie
                  WHERE movie.release_date >= '2012-01-01');

这是子查询的示例。小心这一点，因为它通常很慢......
正如Fluffeh向我指出的那样，你不能选择多个值，并且不得不求助于这样的事情：

SELECT actor_id.name
FROM actor_id
WHERE actor_id.actor_id
          IN ( SELECT IFNULL(movie.star1, IFNULL(movie.star2, movie.star3))
                  FROM movie
                  WHERE movie.release_date >= '2012-01-01');

或者：

SELECT actor_id.name
FROM actor_id
WHERE actor_id.actor_id
          IN ( SELECT IF (movie.star1 <= 12,
                          IF (movie.star2 <= 15,
                              movie.star3,
                              movie.star2),
                          movie.star1)
                  FROM movie
                  WHERE movie.release_date >= '2012-01-01');

Answer 3

使用或声明。我不知道您的数据库结构，但应该使用or：

SELECT actor_id.actor_name,
FROM actor_id 
WHERE (movie.star1 = actor_id.actor_id or movie.star2 = actor_id.actor_id);

Answer 4

SELECT actor_id.actor_name
FROM actor_id WHERE actor_id.actor_id in [specify the values like movie.star2, movie.star3... etc];

但不能在FROM之前使用逗号..

php mysql从一个表中选择多个值

4 个答案: