Question

我想选择按类别和其他自定义字段过滤的自定义字段“portata”的不同值。

这是按类别选择自定义值的查询：

global $wpdb;
$querystr2 = "
SELECT DISTINCT wpostmeta.meta_value 
FROM $wpdb->posts wposts
LEFT JOIN $wpdb->postmeta wpostmeta ON wposts.ID = wpostmeta.post_id 
LEFT JOIN $wpdb->term_relationships ON (wposts.ID = $wpdb->term_relationships.object_id)
LEFT JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id)


WHERE wpostmeta.meta_key = 'portata'
AND $wpdb->term_taxonomy.taxonomy = 'category'
AND $wpdb->term_taxonomy.term_id IN($variabile_c)
ORDER BY wpostmeta.meta_value ASC

";

如何在过滤器上添加其他自定义字段？

Answer 1

您需要再次加入$ wpdb-＆gt; postmeta，为每个联接使用单独的别名，并在WHERE子句中添加几个AND以应用额外条件 - 例如：

 SELECT DISTINCT wpostmeta1.meta_value
   FROM $wpdb->posts wposts
     LEFT JOIN $wpdb->postmeta wpostmeta1 ON wposts.ID = wpostmeta1.post_id 
     LEFT JOIN $wpdb->postmeta wpostmeta2 ON wposts.ID = wpostmeta2.post_id 
     LEFT JOIN $wpdb->term_relationships ON (wposts.ID = $wpdb->term_relationships.object_id)
     LEFT JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id)
   WHERE wpostmeta1.meta_key = 'portata'
     AND wpostmeta2.meta_key = 'other-custom-field-value'
     AND $wpdb->term_taxonomy.taxonomy = 'category'
     AND $wpdb->term_taxonomy.term_id IN($variabile_c)
   ORDER BY wpostmeta1.meta_value ASC

将'other-custom-field-value'替换为您需要过滤的第二个自定义字段值。

Answer 2

谢谢Aaron Miller！现在它有效！

SELECT DISTINCT wpostmeta1.meta_value
FROM $wpdb->posts wposts
     LEFT JOIN $wpdb->postmeta wpostmeta1 ON wposts.ID = wpostmeta1.post_id 
     LEFT JOIN $wpdb->postmeta wpostmeta2 ON wposts.ID = wpostmeta2.post_id 
     LEFT JOIN $wpdb->term_relationships ON (wposts.ID = $wpdb->term_relationships.object_id)
     LEFT JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id)
WHERE wpostmeta1.meta_key = 'portata'
     AND wpostmeta2.meta_key = 'alimentazione'
AND wpostmeta2.meta_value = '$variabile_portata'
     AND $wpdb->term_taxonomy.taxonomy = 'category'
     AND $wpdb->term_taxonomy.term_id IN($variabile_c)
ORDER BY wpostmeta1.meta_value ASC

谢谢Aaron Miller。现在，如果你想通过自定义字段获得另外一个文件管理器，我必须添加1个左连接？谢谢！

wordpress上的高级SQL查询按类别和自定义字段筛选

2 个答案: