worpdressのデータをcustom post と合わせてselectする

wordpressのカスタムポストと合わせてセレクト

LEFT JOIN をつなげて使うことで出力できる。

SELECT p.ID, p.post_name, p.post_title,
custom_post_01.meta_value AS custom_post_01,
custom_post_02.meta_value AS custom_post_02,
custom_post_03.meta_value AS custom_post_03
FROM wp_posts AS p
LEFT JOIN wp_postmeta AS custom_post_01 ON p.ID = custom_post_01.post_id AND 'custom_post_01' = custom_post_01.meta_key
LEFT JOIN wp_postmeta AS custom_post_02 ON p.ID = custom_post_02.post_id AND 'custom_post_02' = custom_post_02.meta_key
LEFT JOIN wp_postmeta AS custom_post_03 ON p.ID = custom_post_03.post_id AND 'custom_post_03' = custom_post_03.meta_key

参考：
http://stackoverflow.com/questions/26319613/improving-a-query-using-a-lot-of-inner-joins-to-wp-postmeta-a-key-value-table