MySQL 8.0

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create table wp_posts (
  ID integer primary key auto_increment,
  post_title varchar(30),
  post_type varchar(30)
);
create table wp_postmeta (
  ID integer primary key auto_increment,
  post_id integer,
  meta_key varchar(30) not null default '_regular_price',
  meta_value integer not null
);
insert into wp_posts (post_title, post_type) values
('Apple Pie','Product'),
('French Toast','Product'),
('Shepards Pie','Product'),
('Jam Pie','Product'),
('Jam Pie','Product'),
('Plate','Not a Product'),
('Bucket','Not a Product'),
('Chequebook','Not a Product'),
('French Toast','Product'),
('French Toast','Product'),
('Banana','Product'),
('Banana','Product'),
('Banana','Product');
insert into wp_postmeta (post_id, meta_value) values
(1,10),
(2,5),
(3,9),
(4,8),
(5,11),
(6,12),
(7,10),
(8,6),
(9,1),
(10,1),
(11,7),
(12,2),
(13,2);
SELECT wp_posts.post_title, MIN(wp_postmeta.meta_value) FROM wp_postmeta JOIN wp_posts
ON wp_postmeta.post_id = wp_posts.id 
WHERE wp_posts.post_type = 'Product' AND wp_postmeta.meta_key = '_regular_price' 
GROUP BY wp_posts.post_title
ORDER BY wp_posts.post_title


post_title
MIN(wp_postmeta.meta_value)


Apple Pie
10

Banana
2

French Toast
1

Jam Pie
8

Shepards Pie
9