Question

道歉，如果这是相当基本的，我有点超出我的深度，可以使用一些指导来填补一些空白。

这是情况...... 我正在查询WordPress数据库，以返回与元键/值条件相关的一组特定条件匹配的帖子子集（具体来说，'dates'的键是否包含与下一个X天相匹配的值）。这很好 - 代码目前是：

$request  = "SELECT DISTINCT ID FROM $wpdb->posts, $wpdb->postmeta";
$request .= " WHERE $wpdb->posts.ID = $wpdb->postmeta.post_id";
$request .= " AND post_status='publish' AND post_type='days'";
$request .= " AND $wpdb->postmeta.meta_key = 'dates' AND $wpdb->postmeta.meta_value >= '$startDate' AND $wpdb->postmeta.meta_value <= '$endDate' AND $wpdb->postmeta.meta_value != '$today'";

现在，我想介绍另一种方案，还返回任何具有* _dayType *键和值月的帖子，其中< em>月是当月。我已经扩展了代码以允许OR规则也返回与该月的第一天匹配的帖子。扩展代码如下所示：

$request  = "SELECT DISTINCT ID FROM $wpdb->posts, $wpdb->postmeta";
$request .= " WHERE $wpdb->posts.ID = $wpdb->postmeta.post_id";
$request .= " AND post_status='publish' AND post_type='days'";
$request .= " AND ";
$request .= " (($wpdb->postmeta.meta_key = 'dates' AND $wpdb->postmeta.meta_value >= '$startDate' AND $wpdb->postmeta.meta_value <= '$endDate' AND $wpdb->postmeta.meta_value != '$today')";
$request .= " OR ";
$request .= " ($wpdb->postmeta.meta_key = 'dates' AND $wpdb->postmeta.meta_value = '$firstDayOfMonth' ))";

现在我遇到了一个问题。我想通过再次查询meta_key变量来扩展返回新月帖子的条件。例如，

$wpdb->postmeta.meta_key = '_dayType' AND $wpdb->postmeta.meta_value = 'month'

但是，添加此内容会返回零结果。我已经测试了查询一个的条件（匹配当月的第一天，或匹配月），我可以返回一个或另一个没问题。我很确定问题是我在同一个字符串中查询同一个变量两次，不考虑排序或区别。重建此查询以恢复的最佳方法是什么：

与下一个X天相匹配的帖子 OR
'月'的帖子

这是最后的加价。问题只是我的AND嵌套语法吗？

$request  = "SELECT DISTINCT ID FROM $wpdb->posts, $wpdb->postmeta";
$request .= " WHERE $wpdb->posts.ID = $wpdb->postmeta.post_id";
$request .= " AND post_status='publish' AND post_type='days'";
$request .= " AND ";
$request .= " (($wpdb->postmeta.meta_key = 'dates' AND $wpdb->postmeta.meta_value >= '$startDate' AND $wpdb->postmeta.meta_value <= '$endDate' AND $wpdb->postmeta.meta_value != '$today')";
$request .= " OR ";
$request .= " (($wpdb->postmeta.meta_key = 'dates' AND $wpdb->postmeta.meta_value = '$firstDayOfMonth') AND ($wpdb->postmeta.meta_key = '_daytype' AND $wpdb->postmeta.meta_value = 'month')) )";

Answer 1

解决;需要通过OR而不是AND来查询多个键，因为变量现在不能同时具有两个值，是吗？

SELECT DISTINCT ID FROM wp_posts, wp_postmeta 
WHERE (
 wp_posts.ID = wp_postmeta.post_id
 AND post_status = 'publish'
 AND post_type = 'days'
 AND (
  wp_postmeta.meta_key = 'dates' 
  AND wp_postmeta.meta_value >= '$startDate' 
  AND wp_postmeta.meta_value <= '$endDate' 
  AND wp_postmeta.meta_value != '$today'
 )
)
UNION
SELECT DISTINCT ID FROM wp_posts, wp_postmeta 
WHERE (
 wp_posts.ID = wp_postmeta.post_id
 AND post_status = 'publish'
 AND post_type = 'days'
 AND (
 (wp_postmeta.meta_key = '_dayType' AND wp_postmeta.meta_key = 'month')
 OR
 (wp_postmeta.meta_key = 'dates' AND wp_postmeta.meta_value = '$firstDayOfMonth' )
 )
)

MySQL / WordPress元查询;结合多个条件

1 个答案: