Query based on custom field

Question

I have made custom fields using advanced custom field plugin. It has a field name school which includes choices such as arts,education,engineering. Now my problem is how can i query only those post who field is arts using wpdb. sincerely i don't know wpdb works. . Any help will be appreciated :)

Answer 1

Try using WP_Query over a direct mysql query. https://codex.wordpress.org/Class_Reference/WP_Query

In your WP_Query arguments include the 'meta_key' and 'meta_value' parameters.

$args = array(
    'meta_key'      => 'school',
    'meta_value'    => 'arts'
);

Answer 2

It's a Wordpress Global Database Access Variable, if you want to executes database related opration than you must use $wpdb

more info : https://codex.wordpress.org/Class_Reference/wpdb