sql查询问题（嵌套AND OR）答案

【问题标题】：problem with sql query (nested AND OR)sql查询问题（嵌套AND OR）
【发布时间】：2011-03-21 22:13:52
【问题描述】：

我正在尝试使用以下查询，但没有得到任何记录：

SELECT wp_posts.* FROM wp_posts 
INNER JOIN wp_term_relationships ON (wp_posts.ID = wp_term_relationships.object_id) 
INNER JOIN wp_postmeta ON (wp_posts.ID = wp_postmeta.post_id) 
INNER JOIN wp_postmeta AS mt1 ON (wp_posts.ID = mt1.post_id) 
INNER JOIN wp_postmeta AS mt2 ON (wp_posts.ID = mt2.post_id) 
WHERE ( wp_term_relationships.term_taxonomy_id IN (92) ) 
AND wp_posts.post_type = 'post' 
AND (wp_posts.post_status = 'publish' OR wp_posts.post_status = 'private' OR wp_posts.post_status = 'future') 
AND wp_postmeta.meta_key = '_inicio_date' 
AND mt1.meta_key = '_inicio_date' 
AND mt2.meta_key = '_eventtimestamp' 
AND ( (mt1.meta_value BETWEEN 20110201 AND 20110231) OR (mt2.meta_value BETWEEN 20110201 AND 20110231) ) 
GROUP BY wp_posts.ID 
ORDER BY wp_posts.post_date asc

但是，如果我这样做：

SELECT wp_posts.* FROM wp_posts 
INNER JOIN wp_term_relationships ON (wp_posts.ID = wp_term_relationships.object_id)   
INNER JOIN wp_postmeta ON (wp_posts.ID = wp_postmeta.post_id) 
INNER JOIN wp_postmeta AS mt1 ON (wp_posts.ID = mt1.post_id) 
INNER JOIN wp_postmeta AS mt2 ON (wp_posts.ID = mt2.post_id) 
WHERE ( wp_term_relationships.term_taxonomy_id IN (92) ) 
AND wp_posts.post_type = 'post' 
AND (wp_posts.post_status = 'publish' OR wp_posts.post_status = 'private' OR wp_posts.post_status = 'future') 
AND wp_postmeta.meta_key = '_inicio_date' 
AND mt1.meta_key = '_inicio_date' 
AND mt2.meta_key = '_eventtimestamp' 
AND (mt1.meta_value BETWEEN 20110201 AND 20110231) 
OR (mt2.meta_value BETWEEN 20110201 AND 20110231) 
GROUP BY wp_posts.ID 
ORDER BY wp_posts.post_date asc

它获取记录，但忽略所有带有“OR”的记录的前面的“AND”

如何嵌套最后一个“AND”和“OR”？

谢谢

【问题讨论】：

期望的条件是什么，请解释... 哪个条件结果失败，请分享您的分析.....
条件 AND ( (mt1.meta_value BETWEEN 20110201 AND 20110231) OR (mt2.meta_value BETWEEN 20110201 AND 20110231) )
条件“AND ( (mt1.meta_value BETWEEN 20110201 AND 20110231) OR (mt2.meta_value BETWEEN 20110201 AND 20110231) )”失败，没有找到记录
@Mario，正如 Nitin 建议的那样，这是嵌套这两个条件的方式。您可能没有任何记录满足您在 #1 中指定的所有条件。
您是否 100% 确定您确实有满足第一条语句的记录？

标签： mysql database wordpress

【解决方案1】：

在我看来，wp_posts 中的一个条目可能没有 wp_postmeta 表中的两个连接记录，所以更改

INNER JOIN wp_postmeta AS mt1 ON (wp_posts.ID = mt1.post_id) 
INNER JOIN wp_postmeta AS mt2 ON (wp_posts.ID = mt2.post_id)

到

LEFT JOIN wp_postmeta AS mt1 ON (wp_posts.ID = mt1.post_id) 
LEFT JOIN wp_postmeta AS mt2 ON (wp_posts.ID = mt2.post_id)

还有一点：使用 BETWEEN 时要小心：

为了在将 BETWEEN 与日期或时间值一起使用时获得最佳结果，请使用 CAST() 将值显式转换为所需的数据类型。示例：如果将 DATETIME 与两个 DATE 值进行比较，请将 DATE 值转换为 DATETIME 值。如果在与 DATE 的比较中使用字符串常量（例如 '2001-1-1'），请将字符串转换为 DATE。

【讨论】：

它没有用，我尝试在最后两个条件中使用带和不带括号：AND (mt1.meta_value BETWEEN 20110201 AND 20110231) OR (mt2.meta_value BETWEEN 20110201 AND 20110231)
你确定数据库中有满足查询的记录吗？？
也许我不清楚：我想要最后一个条件“AND ( (mt1.meta_value BETWEEN 20110201 AND 20110231) OR (mt2.meta_value BETWEEN 20110201 AND 20110231) )”来查找任何具有 mt1 的记录这些值之间的 .meta_value 或 mt2.meta_value
我在使用 CAST，但我删除它以检查它是否导致错误

【解决方案2】：

它使用这个工作：

SELECT wp_posts.* FROM wp_posts 
INNER JOIN wp_term_relationships ON (wp_posts.ID = wp_term_relationships.object_id) 
INNER JOIN wp_postmeta ON (wp_posts.ID = wp_postmeta.post_id) 
LEFT JOIN wp_postmeta AS mt1 ON (wp_posts.ID = mt1.post_id) 
LEFT JOIN wp_postmeta AS mt2 ON (wp_posts.ID = mt2.post_id) 
WHERE ( wp_term_relationships.term_taxonomy_id IN (".$categoria.") ) 
AND wp_posts.post_type = 'post' 
AND (wp_posts.post_status = 'publish' OR wp_posts.post_status = 'private' OR     wp_posts.post_status = 'future') 
AND ( ( mt1.meta_key = '_incio_date' AND (mt1.meta_value BETWEEN 20110201 AND 20110231) ) OR (mt2.meta_key = '_eventtimestamp' AND (mt2.meta_value BETWEEN 20110201 AND 20110231) ) )
GROUP BY wp_posts.ID ORDER BY wp_posts.post_date asc

【讨论】：