SQL запроса:

SELECT   wp67_posts.*
					 FROM wp67_posts  LEFT JOIN wp67_term_relationships ON (wp67_posts.ID = wp67_term_relationships.object_id) INNER JOIN wp67_postmeta ON ( wp67_posts.ID = wp67_postmeta.post_id )
					 WHERE 1=1  AND ( 
  wp67_term_relationships.term_taxonomy_id IN (14,29)
) AND ( 
  wp67_postmeta.meta_key = 'average_price_week'
) AND wp67_posts.post_type = 'boats' AND ((wp67_posts.post_status = 'publish'))
					 GROUP BY wp67_posts.ID
					 ORDER BY wp67_postmeta.meta_value+0 DESC
					 

Первые 20 постов и meta:

ID: 632 — title: Fountaine Pajot Belize 43 - Piropo — meta: ['']
ID: 619 — title: Lagoon 380 - Marlene — meta: ['']
ID: 620 — title: Fountaine Pajot Bahia 46 - Carlos — meta: ['']
ID: 621 — title: Lagoon 421 - Marimar — meta: ['']
ID: 622 — title: Lagoon 410 - Sofia — meta: ['']
ID: 623 — title: Fountaine Pajot Athena 38 - La Perla — meta: ['']
ID: 624 — title: Fountaine Pajot Lavezzi 40 - Kupela — meta: ['']
ID: 625 — title: Voyage 440 - Ron Punch — meta: ['']
ID: 626 — title: Lagoon 440 - Victoria — meta: ['']
ID: 627 — title: Lagoon 421 - Estrella — meta: ['']
ID: 628 — title: Fountaine Pajot Eleuthera 60 - Andromeda — meta: ['']
ID: 630 — title: Leopard 44 - La Luna — meta: ['']
ID: 631 — title: Lagoon 450 F - Mariano — meta: ['']