選擇所有帶有搜索標簽的帖子（和相關標簽）

Question

我想選擇標有一個或多個搜索詞的帖子（及其標簽）。

這是我的表：

郵政

| ID | community | created             | updated             | title | content |
|----|-----------|---------------------|---------------------|-------|---------|
| 99 | 17        | 2019-08-14 14:20:38 | 2019-08-14 14:20:38 | Lorem | Ipsum   |
| 80 | 16        | 2019-07-27 23:11:07 | 2019-07-27 23:11:07 | Lorem | Ipsum   |
| 79 | 16        | 2019-07-27 23:09:47 | 2019-07-27 23:09:47 | Lorem | Ipsum   |

社區

| ID | title          |
|----|----------------|
| 16 | The Scary Door |
| 17 | Other          |

社區標簽類別

| Community | Category |
|-----------|----------|
| 16        | 5        |
| 16        | 18       |
| 16        | 19       |
| 16        | 20       |
| 17        | 6        |

標簽類別

| category    | ID |
|-------------|----|
| character   | 5  |
| focus       | 18 |
| warning     | 19 |
| time-period | 20 |
| NULL        | 6  |

標簽分類

| category | tag |
|----------|-----|
| 5        | 146 |
| 6        | 131 |
| 6        | 147 |
| 19       | 147 |
| 20       | 148 |

標簽

| name          | id  |
|---------------|-----|
| spider        | 146 |
| arachnophobia | 147 |
| Victorian era | 148 |
| NULL          | 131 |

帖子標簽

| post | tag |
|------|-----|
| 99   | 147 |
| 80   | 146 |
| 80   | 147 |
| 80   | 148 |
| 79   | 131 |

我已經在使用這個查詢來獲取所有帖子及其相關標簽和類別的信息：

SELECT p.id, c.id as 'commid', c.title AS 'community', p.title, p.content, p.author, p.created, p.updated, ct.category, t.name AS 'tag'
FROM Post p, Community c, CommunityTagCategories cc, TagCategory ct, TagCategorised tc, Tag t, PostTags pt
WHERE p.community=c.id AND c.id=cc.community AND cc.category=ct.id AND ct.id=tc.category AND tc.tag=t.id AND t.id=pt.tag AND pt.post=p.id
ORDER BY p.created DESC;

如果我搜索像“arachnophobia”這樣的標簽，我希望結果可以像這樣縮小范圍：（如果我想搜索“arachnophobia”和“spider”，它應該只顯示 80 后的信息）

| ID | commid | community      | title | content | author | created             | updated             | category    | tag           |
|----|--------|----------------|-------|---------|--------|---------------------|---------------------|-------------|---------------|
| 99 | 17     | Other          | Lorem | Lorem   | 7      | 2019-08-14 14:20:38 | 2019-08-14 14:20:38 | NULL        | arachnophobia |
| 80 | 16     | The Scary Door | Lorem | Lorem   | 7      | 2019-07-27 23:11:07 | 2019-07-27 23:11:07 | character   | spider        |
| 80 | 16     | The Scary Door | Lorem | Lorem   | 7      | 2019-07-27 23:11:07 | 2019-07-27 23:11:07 | warning     | arachnophobia |
| 80 | 16     | The Scary Door | Lorem | Lorem   | 7      | 2019-07-27 23:11:07 | 2019-07-27 23:11:07 | time-period | Victorian era |

通過搜索類似的問題，似乎我可能需要使用嵌套的 SELECT 和 INNER JOINS。 我試着這樣做：

SELECT p2.id, c.id as 'commid', c.title AS 'community', p2.author, p2.created, p2.updated, p2.title, p2.content, tc.category, t.name AS 'tag' 
FROM 
    (SELECT p.id
    FROM Post p, Tag t, PostTags pt
    WHERE p.id=pt.post AND pt.tag=t.id AND t.name ="arachnophobia"
    ) search
INNER JOIN Post p2
ON (search.id = p2.id)
INNER JOIN Community c
ON p2.community=c.id
INNER JOIN CommunityTagCategories cc
ON c.id=cc.community
INNER JOIN TagCategory tc
ON cc.category=tc.id
INNER JOIN TagCategorised ct
ON tc.id=ct.category
INNER JOIN Tag t
ON ct.tag=t.id
INNER JOIN PostTags pt
ON t.id=pt.tag
INNER JOIN Post p3
ON pt.post=p3.id
ORDER BY p2.created DESC;       

它只返回帖子 99 和 80 的結果，但它為我提供了相關社區中存在的每個標簽和類別的結果，即使這些帖子與這些標簽和類別無關。 所以這里它返回一個額外的 80 行，帶有來自 79 號帖子的標簽，它們都在同一個社區中。

| ID | commid | community      | title | content | author | created             | updated             | category    | tag           |
|----|--------|----------------|-------|---------|--------|---------------------|---------------------|-------------|---------------|
| 99 | 17     | Other          | Lorem | Lorem   | 7      | 2019-08-14 14:20:38 | 2019-08-14 14:20:38 | NULL        | arachnophobia |
| 80 | 16     | The Scary Door | Lorem | Lorem   | 7      | 2019-07-27 23:11:07 | 2019-07-27 23:11:07 | character   | spider        |
| 80 | 16     | The Scary Door | Lorem | Lorem   | 7      | 2019-07-27 23:11:07 | 2019-07-27 23:11:07 | warning     | arachnophobia |
| 80 | 16     | The Scary Door | Lorem | Lorem   | 7      | 2019-07-27 23:11:07 | 2019-07-27 23:11:07 | time-period | Victorian era |
| 80 | 16     | The Scary Door | Lorem | Lorem   | 7      | 2019-07-27 23:11:07 | 2019-07-27 23:11:07 | character   | NULL          |

我問過類似的問題，關於前幾天顯示的所有數據后在這里和用戶NBK幫忙解決了不同的查詢也有效，但它是一個有點復雜，我知道如何改變自己。

Answer 1

為避免重復行，您可以使用 DISTINCT：

SELECT DISTINCT p2.id
  , c.id as commid
  , c.title AS community
  , p2.author
  , p2.created
  , p2.updated
  , p2.title
  , p2.content
  , tc.category
  , t.name AS tag 
FROM  (
   SELECT p.id
   FROM Post p
   INNER JOIN PostTags pt ON p.id=pt.post
   INNER JOIN Tag t ON  pt.tag=t.id AND t.name ="arachnophobia"
) search
INNER JOIN Post p2 ON search.id = p2.id
INNER JOIN Community c ON p2.community=c.id
INNER JOIN CommunityTagCategories cc ON c.id=cc.community
INNER JOIN TagCategory tc ON cc.category=tc.id
INNER JOIN TagCategorised ct ON tc.id=ct.category
INNER JOIN Tag t ON ct.tag=t.id
INNER JOIN PostTags pt ON t.id=pt.tag
INNER JOIN Post p3 ON pt.post=p3.id
ORDER BY p2.created DESC;     

只是一些建議。

你不應該在列名周圍使用單引號（如果是文字文本）在需要時使用反引號。

不應使用基於表名逗號分隔的舊隱式連接語法和 where 條件（您在子查詢中有）。

避免在連接條件周圍使用不必要的 ()。

並查看您的關系：您應該避免加入您已經通過搜索獲得的標簽的最后一部分。

SELECT DISTINCT p2.id
  , c.id as commid
  , c.title AS community
  , p2.author
  , p2.created
  , p2.updated
  , p2.title
  , p2.content
  , tc.category
  , t.name AS tag 
FROM  (
    SELECT p.id
    FROM Post p
    INNER JOIN Tag t ON p.id=pt.post AND t.name ="arachnophobia"
    INNER JOIN PostTags pt ON pt.tag=t.id 
) search
INNER JOIN Post p2 ON search.id = p2.id
INNER JOIN Community c ON p2.community=c.id
INNER JOIN CommunityTagCategories cc ON c.id=cc.community
INNER JOIN TagCategory tc ON cc.category=tc.id
INNER JOIN TagCategorised ct ON tc.id=ct.category
ORDER BY p2.created DESC;