WordPress Theme Development | POST related functions

1. Reference help: https://codex.wordpress.org 
2. get_posts( array $args = null )
1. Return list of latest posts [object]
2. Shows posts matching principle.
3. get_post ( int|WP_Post|null $post = null, string $output = OBJECT, string $filter = 'raw' )
1. Post ID returns Post date or object
4. wp_delete_post(int $postid, bool $force_delete = false )
1. Permanently delete post/page based in post ID.
2. Works when force_delete true, what ever the post is in trash, draft, private or public. 
3. Equivalent Code
   global $wpdb;
   $wpdb->query( 'DELETE FROM wp_posts WHERE post_type = "abc" ' );
   $wpdb->query( 'DELETE FROM wp_postmeta WHERE post_id NOT IN (SELECT id FORM wp_posts)' );
   $wpdb->query( 'DELETE FROM wp_term_relationships WHERE object_id NOT IN (SELECT id FROM wp_posts)' );
5.