Question

我正在为招聘信息网站制作搜索功能。为此，我需要首先显示具有匹配标题的列表，然后显示具有匹配描述的作业列表。这是我现在正在使用的查询：

示例：

(SELECT * FROM `jobs` WHERE title LIKE '%java%developer%') 
UNION DISTINCT 
(SELECT * FROM `jobs` WHERE description LIKE '%java%developer%')

但是，我还需要按时间戳对结果进行排序，以便首先显示最新结果。就像它应该给出具有按时间戳排序的匹配标题的结果，然后是按时间戳排序的具有匹配描述的列表。

Answer 1

我可能会写类似的查询：

  select *, ((title like '%…%')*2 + (description like '%…%')) as rank
    from jobs
   where title like '%…%'
      or description like '%…%'
order by rank desc, time desc

这样，标题和描述匹配的行将首先出现，然后是title-matches，然后是description-matches。我还没有测试过，但通常mysql在将bool转换为int方面做得很好（true：1，false：0）

Answer 2

尝试此操作，将timestamp替换为时间戳列的名称

(SELECT *, 1 as unionsorting FROM `jobs` WHERE title LIKE '%java%developer%' ORDER BY timestamp desc)
UNION DISTINCT
(SELECT *, 2 as unionsorting FROM `jobs` WHERE description LIKE '%java%developer%' ORDER BY timestamp desc)
ORDER BY unionsorting

但是做2个查询可能更快（必须进行测试）

SELECT * FROM `jobs` WHERE title LIKE '%java%developer%' ORDER BY timestamp desc
SELECT * FROM `jobs` WHERE description LIKE '%java%developer%' ORDER BY timestamp desc

Answer 3

已修改以修复...

这有点笨重，但有些变化可行：

SELECT title, description, timestamp_column, min(rank) from 
(
    (SELECT *, 1 as rank FROM `jobs` WHERE title LIKE '%java%developer%') 
    UNION
    (SELECT *, 2 as rank FROM `jobs` WHERE description LIKE '%java%developer%')
) x
GROUP BY title, description, timestamp_column 
ORDER BY min(rank), timestamp_column DESC

这使用GROUP BY子句代替DISTINCT

Answer 4

SELECT * 
FROM `jobs` 
WHERE (title LIKE '%java%developer%' OR description LIKE '%java%developer%')
ORDER BY (CASE WHEN title LIKE '%java%developer%' THEN 0 ELSE 1 END), timestamp_col DESC

Answer 5

(SELECT * FROM `jobs` A WHERE title LIKE '%java%developer%' ORDER BY A.colDateTime desc) 
UNION DISTINCT 
(SELECT * FROM `jobs` B WHERE description LIKE '%java%developer%' ORDER BY B.colDateTime desc)

在MySQL中对联合查询进行排序

5 个答案: