PHP, MySQL select, order by field and group it

Question

欢迎!

我的 SQL 查询有问题。

我的每个用户都有一个包含已查看标签的唯一表格。我想给他看他能引起他兴趣的东西，但我无法应付对数据库的查询...

用户 X 有标签:

tag_id 8 viewed 150 times
tag_id 11 viewed 100 times
tag_id 12 viewed 80 times

这是我的问题:

SELECT c.id AS cid, c.value, t.id AS tag_id, t.value AS tag_name 
FROM components c 
JOIN connect_tag_com ctc ON ctc.component_id = c.id 
JOIN tags t ON t.id = ctc.tag_id 
WHERE t.id IN('8', '11', '12') 
ORDER BY FIELD (t.id, '8', '11', '12') ASC, c.id DESC

到这个数据库:http://sqlfiddle.com/#!9/904d1a/6

结果:

| id |                   value | id |      value |
|----|-------------------------|----|------------|
|  8 | article about beetroots |  8 | refreshing |
|  7 |     article about pears |  8 | refreshing |
|  5 |    article about apples |  8 | refreshing |
|  4 |  article about cucumber |  8 | refreshing |
|  1 |   article about carrots |  8 | refreshing |
|  8 | article about beetroots | 11 |      sweet |
|  7 |     article about pears | 11 |      sweet |
|  6 |   article about berries | 11 |      sweet |
|  3 |   article about bananas | 11 |      sweet |
|  1 |   article about carrots | 11 |      sweet |
|  8 | article about beetroots | 12 | wegetables |
|  4 |  article about cucumber | 12 | wegetables |
|  2 |    article about onions | 12 | wegetables |
|  1 |   article about carrots | 12 | wegetables |

现在我只剩下 group by c.id 组件，不幸的是，这破坏了整个哲学，因为查询的任务是按照我观看的标签的顺序查找资料。因此，如果 c.id 4 具有标签 8 和 12，作为查询的结果，应该只接收带有搜索标签的 c.id 4首先，标记 8。第二个标签 - 12 被省略。

你明白了吗？

这就是我所说的:

对于标签:8、11、12

|c.id|                   value |t.id|      value |
|----|-------------------------|----|------------|
|  8 | article about beetroots |  8 | refreshing |
|  7 |     article about pears |  8 | refreshing |
|  5 |    article about apples |  8 | refreshing |
|  4 |  article about cucumber |  8 | refreshing |
|  1 |   article about carrots |  8 | refreshing |
|  6 |   article about berries | 11 |      sweet |
|  3 |   article about bananas | 11 |      sweet |
|  2 |    article about onions | 12 | wegetables |

只有唯一的 ID。我知道我可以用 SUBQUERY 做到这一点，但我不知道该怎么做。你能帮忙吗？

祝你有美好的一天!

Answer 1

我确信这里的子查询比绝对必要的要多，但出于某种原因，没有它们我无法让它工作......

SELECT cid
     , value
     , tag_id
     , tag_name
  FROM 
     ( SELECT cid
     , value
     , tag_id
     , tag_name
     , CASE WHEN @prev = cid THEN @i:=@i+1 ELSE @i:=1 END i
     , @prev := cid
  FROM 
     ( SELECT c.id cid
            , c.value
            , t.id tag_id
            , t.value tag_name 
         FROM components c
         JOIN connect_tag_com ctc 
           ON ctc.component_id = c.id 
         JOIN tags t 
           ON t.id = ctc.tag_id 
        WHERE t.id IN(8,11,12)
     ) x
  JOIN ( SELECT @prev:=null,@i:=0 ) vars
 ORDER 
    BY value
     , FIELD(tag_id,8,11,12) ASC
     ) n
  WHERE i = 1  ORDER 
    BY FIELD(tag_id,8,11,12) ASC
     , value;