wordpress $ wpbd-> get_results不起作用？

Question

This is my query.

SELECT post_id
FROM wp_postmeta
WHERE meta_key = 'app_trailer-type'
AND meta_value = 'Bulk Liquid (Tanker)'
AND post_id
IN (

SELECT post_id
FROM wp_postmeta
WHERE meta_key = 'app_additional-hiring-states'
AND meta_value LIKE 'Arkansas (AR)%'
)
LIMIT 0 , 30

When I run this query directly in the database one record is returned.

But when I run this query with $wpdb->results($query); or $wpdb->results($query, OBJECT); it returns NULL.

Answer 1

change $wpdb->results($query);

to

$wpdb->get_results($query);

get_results() function returns the entire query result as an array...try it