Question

根据评论进行编辑

我有2个表帖子和类别。结构和样本数据如下：

POSTS
ID    NAME                  DESCRIPTION              CATEGORY_ID
--  -----------------   -------------------          -----------
1   For Song Lovers     A post all about music            8
2   For Music Lovers    About passion of music            8
3   I love songs        Listing favourite songs           8
4   Rock Music          ImagineDragon                     6
5   Retro Music         Old choice musical themes         7

CATEGORIES
ID    NAME
--  -----------------
6   Artists
7   Entertainment
8   Music

我想以这样的方式对记录进行排序：

首先显示名称，描述和类别名称中匹配关键字的帖子，然后是
在名称中匹配关键字的帖子，描述后跟
名称中匹配关键字后跟
描述中匹配关键字的帖子，后跟
类别

关键字

我希望得到的结果是（如果 keyword = music ）：

OUTPUT
---------
Post ID#2
Post ID#5
Post ID#4
Post ID#1
Post ID#3

我已经能够编写5个查询并将其组合起来以获得唯一记录。但这不是优化的解决方案。这是我试过的：

(
SELECT "posts".* FROM "posts" INNER JOIN "categories" ON "categories"."id" = "posts"."category_id" WHERE posts.name iLIKE ('%music%') AND posts.description iLIKE ('%music%') AND categories.name iLIKE ('%music%')
+
SELECT "posts".* FROM "posts" WHERE posts.name iLIKE ('%music%') AND posts.description iLIKE ('%music%')
+
SELECT "posts".* FROM "posts"  WHERE posts.name iLIKE ('%music%')
+
SELECT "posts".* FROM "posts"  WHERE posts.description iLIKE ('%music%')
+
SELECT "posts".* FROM "posts" INNER JOIN "categories" ON "categories"."id" = "posts"."category_id" WHERE categories.name iLIKE ('%music%')
).uniq

我甚至尝试编写单个查询，但这并没有返回我想要的结果（明显的原因是我没有使用GROUP OR COUNT）

SELECT posts.* FROM posts INNER JOIN categories ON categories.id = posts.category_id
WHERE (
  (posts.name iLIKE ('%music%') AND posts.description iLIKE ('%music%') AND categories.name iLIKE ('%music%'))
  OR (posts.name iLIKE ('%music%') AND posts.description iLIKE ('%music%'))
  OR (posts.name iLIKE ('%music%'))
  OR (posts.description iLIKE ('%music%'))
  OR (categories.name iLIKE ('%music%')))

请建议我如何使用上述SQL实现相同的目标。

环境详情：

数据库：PostgreSQL

版本：postgres（PostgreSQL）9.4.5

Answer 1

据我所知，PostgreSQL支持布尔值，因此这应符合您的描述，按单独的列排序：

SELECT posts.* FROM posts INNER JOIN categories ON categories.id = posts.category_id
WHERE  -- can be simplified to 
      LOWER(posts.name)        iLIKE ('%music%')
   OR LOWER(posts.description) iLIKE ('%music%')
   OR LOWER(categories.name)   iLIKE ('%music%')
ORDER BY -- FALSE probably sorts lower than TRUE, thus DESC
  LOWER(posts.name)        iLIKE ('%music%') DESC, posts.name,
  LOWER(posts.description) iLIKE ('%music%') DESC, posts.description
  LOWER(categories.name)   iLIKE ('%music%') DESC, categories.name

另一个评论：iLike不区分大小写，为什么然后应用LOWER？这应该返回相同的结果：

SELECT posts.* FROM posts INNER JOIN categories ON categories.id = posts.category_id
WHERE  -- can be simplified to 
      posts.name        iLIKE ('%music%')
   OR posts.description iLIKE ('%music%')
   OR categories.name   iLIKE ('%music%')
ORDER BY -- FALSE probably sorts lower than TRUE, thus DESC
   posts.name        iLIKE ('%music%') DESC, posts.name,
   posts.description iLIKE ('%music%') DESC, posts.description
   categories.name   iLIKE ('%music%') DESC, categories.name

现在结合@ JuanCarlosOropeza的答案： - ）

Answer 2

 ORDER BY 
       CASE WHEN LOWER(posts.name) iLIKE ('%music%') THEN posts.name END,
       CASE WHEN LOWER(posts.description) iLIKE ('%music%') THEN posts.description END,
       CASE WHEN LOWER(categories.name) iLIKE ('%music%') THEN categories.name END,

Answer 3

感谢@ juan-carlos-oropeza和@dnoeth的回复。根据您的建议和摘要，我在下面提出并能够解决此问题

ORDER BY
  CASE WHEN posts.name iLIKE ('%music%') AND posts.description iLIKE ('%music%') AND categories.name iLIKE ('%music%') THEN 0 END,
  CASE WHEN posts.name iLIKE ('%music%') AND posts.description iLIKE ('%music%') THEN 1 END,
  CASE WHEN posts.name iLIKE ('%music%') THEN 2 END,
  CASE WHEN posts.description iLIKE ('%music%') THEN 3 END,
  CASE WHEN categories.name iLIKE ('%music%') THEN 4 END

Postgresql：根据表列中的最大匹配数对结果进行排序

3 个答案: