单个查询中的多个 MySQL 计数

Question

目前我有多个查询，1 想将其合并为一个，它们是相同的，只是日期范围在变化：

查询 1 :

SELECT COUNT(simp_posts.ID)
FROM simp_posts
INNER JOIN simp_postmeta
ON ( simp_posts.ID = simp_postmeta.post_id )
WHERE ( ( simp_postmeta.meta_key = '_schedule_end' AND simp_postmeta.meta_value = '0' AND simp_posts.post_status = 'wc-active'))
OR ( ( simp_postmeta.meta_key = '_schedule_end' AND simp_postmeta.meta_value > '2018-08-01 23:33:51' AND simp_posts.post_status = 'wc-active'))
OR ( ( simp_postmeta.meta_key = '_schedule_end' AND simp_postmeta.meta_value > '2018-08-01 23:33:51' AND simp_posts.post_status = 'wc-pending-cancel'))

查询 2 :

SELECT COUNT(simp_posts.ID)
FROM simp_posts
INNER JOIN simp_postmeta
ON ( simp_posts.ID = simp_postmeta.post_id )
WHERE ( ( simp_postmeta.meta_key = '_schedule_end' AND simp_postmeta.meta_value = '0' AND simp_posts.post_status = 'wc-active'))
OR ( ( simp_postmeta.meta_key = '_schedule_end' AND simp_postmeta.meta_value > '2018-09-01 23:33:51' AND simp_posts.post_status = 'wc-active'))
OR ( ( simp_postmeta.meta_key = '_schedule_end' AND simp_postmeta.meta_value > '2018-09-01 23:33:51' AND simp_posts.post_status = 'wc-pending-cancel'))

查询 3 :

SELECT COUNT(simp_posts.ID)
FROM simp_posts
INNER JOIN simp_postmeta
ON ( simp_posts.ID = simp_postmeta.post_id )
WHERE ( ( simp_postmeta.meta_key = '_schedule_end' AND simp_postmeta.meta_value = '0' AND simp_posts.post_status = 'wc-active'))
OR ( ( simp_postmeta.meta_key = '_schedule_end' AND simp_postmeta.meta_value > '2018-10-01 23:33:51' AND simp_posts.post_status = 'wc-active'))
OR ( ( simp_postmeta.meta_key = '_schedule_end' AND simp_postmeta.meta_value > '2018-10-01 23:33:51' AND simp_posts.post_status = 'wc-pending-cancel'))

我希望将这些查询合并为一个，结果是 3 行，每个计数的结果合而为一。例如我会得到： 182 183 194

感谢您的帮助

Answer 1

具有where中的共同条件并在日期范围内有条件地聚合。请注意@Tim 在评论中提到的内容。如果计数必须互斥，请在 case 表达式中包含 meta_value 的范围。

SELECT COUNT(CASE WHEN simp_postmeta.meta_value > '2018-08-01 23:33:51' 
                  THEN simp_posts.ID END)
,COUNT(CASE WHEN simp_postmeta.meta_value > '2018-09-01 23:33:51' 
            THEN simp_posts.ID END)
,COUNT(CASE WHEN simp_postmeta.meta_value > '2018-10-01 23:33:51' 
            THEN simp_posts.ID END)
FROM simp_posts
INNER JOIN simp_postmeta ON simp_posts.ID = simp_postmeta.post_id
WHERE simp_postmeta.meta_key = '_schedule_end' 
AND simp_posts.post_status IN ('wc-active','wc-pending-cancel')

Answer 2

在 MySQL 中，您可以使用带有布尔值的 SUM() 来简化答案。

你的逻辑很复杂。我认为它减少到：

SELECT SUM((pm.meta_value = '0' AND p.post_status = 'wc-active') or pm.meta_value > '2018-09-01 23:33:51'),
       SUM((pm.meta_value = '0' AND p.post_status = 'wc-active') or pm.meta_value > '2018-10-01 23:33:51'),
SUM((pm.meta_value = '0' AND p.post_status = 'wc-active') or pm.meta_value > '2018-10-01 23:33:51')
FROM simp_posts p INNER JOIN
     simp_postmeta pm
     ON p.ID = pm.post_id
WHERE pm.meta_key = '_schedule_end' AND
      p.post_status IN ('wc-active', 'wc-pending-cancel')

单个查询中的多个 MySQL 计数

Multiple MySQL count in a single query

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