Using WordPress ‘get_posts_by_author_sql()’ PHP function

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The get_posts_by_author_sql() WordPress PHP function retrieves the SQL query for posts based on capability, author, and type.

Usage

Here’s a generic example of how to use the function:

$where = get_posts_by_author_sql('post');
echo $where;

Parameters

  • $post_type (string|array): Required. Single post type or an array of post types.
  • $full (bool): Optional. Returns a full WHERE statement instead of just an ‘andalso’ term. Default: true.
  • $post_author (int): Optional. Query posts having a single author ID. Default: null.
  • $public_only (bool): Optional. Only return public posts. Skips cap checks for $current_user. Default: false.

More information

See WordPress Developer Resources: get_posts_by_author_sql

Note: The full option set to false currently doesn’t return the post filter as you would expect. See this patch and test for more info: https://core.trac.wordpress.org/ticket/30354

Examples

Get posts by author

This example retrieves posts by a specific author with ID 5:

$author_id = 5;
$where = get_posts_by_author_sql('post', true, $author_id);
echo $where;

Get public posts only

This example retrieves only public posts:

$public_only = true;
$where = get_posts_by_author_sql('post', true, null, $public_only);
echo $where;

Get posts of custom post type

This example retrieves posts of a custom post type called ‘book’:

$where = get_posts_by_author_sql('book');
echo $where;

Get posts of multiple post types

This example retrieves posts of multiple post types, ‘post’ and ‘page’:

$post_types = array('post', 'page');
$where = get_posts_by_author_sql($post_types);
echo $where;

Get post ID by title

This example retrieves the post ID of a post with the title “Hello world!”:

$where = get_posts_by_author_sql('post');
global $wpdb;
$query = "SELECT ID FROM $wpdb->posts $where AND post_title = %s";
$post_id = $wpdb->get_var($wpdb->prepare($query, 'Hello world!'));
echo $post_id;