Question

我有这个查询在两个SQL表中搜索。我正在寻找一种方法来按事件排序结果。这是我的问题：

SELECT `parent_id`
FROM wp_forum_posts
WHERE text LIKE '%{$term1}%'
UNION
SELECT `id`
FROM wp_forum_threads
WHERE subject LIKE '%{$term1}%

获得结果的最佳方法是什么？

Answer 1

诀窍是首先使用UNION ALL，它保留重复项（普通UNION删除重复项），然后从该结果中选择。这个查询应该这样做：

select * from (
    select parent_id as mID, count(*) as cnt
    from wp_forum_posts
    where text like '%{$term1}%'
    group by 1
  UNION ALL
    select id, count(*)
    FROM wp_forum_threads
    where subject like '%{$term1}%
    group by 1) x
order by 2, 1

Answer 2

假设ID和parent_ID在表中不重复，否则每个id可以获得2行......如果是，那么你是否希望将它们相加在一起？与父ID和ID相关？

Select mID, cnt
FROM 
(SELECT `parent_id` as mID, count(`parent_ID`) as cnt
FROM wp_forum_posts
WHERE text LIKE '%{$term1}%'
Group by `parent_ID`
UNION
SELECT `id`, count(`id`) as cnt
FROM wp_forum_threads
WHERE subject LIKE '%{$term1}%
GROUP BY `id`)
Order by cnt ASC, mID

在两个表中搜索并按术语的顺序排序

2 个答案: