wpdb::get_col( string|null $query = null, int $x )

Retrieve one column from the database.

Description

Executes a SQL query and returns the column from the SQL result. If the SQL result contains more than one column, this function returns the column specified. If $query is null, this function returns the specified column from the previous SQL result.

Parameters

$query

(string|null) (Optional) SQL query. Defaults to previous query.

Default value: null

$x

(int) (Optional) Column to return. Indexed from 0.

Return

(array) Database query result. Array indexed from 0 by SQL result row number.

Source

File: wp-includes/wp-db.php 

	public function get_col( $query = null , $x = 0 ) {
		if ( $this->check_current_query && $this->check_safe_collation( $query ) ) {
			$this->check_current_query = false;
		}

		if ( $query ) {
			$this->query( $query );
		}

		$new_array = array();
		// Extract the column values
		if ( $this->last_result ) {
			for ( $i = 0, $j = count( $this->last_result ); $i < $j; $i++ ) {
				$new_array[ $i ] = $this->get_var( null, $x, $i );
			}
		}
		return $new_array;
	}

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Related

Uses

Uses
Uses Description
wp-includes/wp-db.php: wpdb::check_safe_collation()

Check if the query is accessing a collation considered safe on the current version of MySQL.
wp-includes/wp-db.php: wpdb::query()

Perform a MySQL database query, using current database connection.
wp-includes/wp-db.php: wpdb::get_var()

Retrieve one variable from the database.

Used By

Used By
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wp-includes/author-template.php: is_multi_author()

Does this site have more than one author
wp-includes/deprecated.php: get_usermeta()

Retrieve user metadata.
wp-includes/class-wp-user-query.php: WP_User_Query::query()

Execute the query, with the current variables.
wp-includes/class-wp-query.php: WP_Query::get_posts()

Retrieve the posts based on query variables.
wp-includes/class-wp-network-query.php: WP_Network_Query::get_network_ids()

Used internally to get a list of network IDs matching the query vars.
wp-includes/comment.php: do_all_pings()

Perform all pingbacks, enclosures, trackbacks, and send to pingback services.
wp-includes/comment.php: wp_delete_comment()

Trashes or deletes a comment.
wp-includes/meta.php: update_metadata()

Update metadata for the specified object. If no value already exists for the specified object ID and metadata key, the metadata will be added.
wp-includes/meta.php: delete_metadata()

Delete metadata for the specified object.
wp-includes/user.php: wp_get_users_with_no_role()

Get the user IDs of all users with no role on this site.
wp-includes/user.php: count_users()

Count number of users who have each of the user roles.
wp-includes/post.php: wp_delete_auto_drafts()

Delete auto-drafts for new posts that are > 7 days old.
wp-includes/post.php: wp_delete_attachment()

Trash or delete an attachment.
wp-includes/post.php: get_all_page_ids()

Get a list of page IDs.
wp-includes/post.php: wp_delete_post()

Trash or delete a post or page.
wp-includes/class-wp-site-query.php: WP_Site_Query::get_site_ids()

Used internally to get a list of site IDs matching the query vars.
wp-includes/ms-functions.php: remove_user_from_blog()

Remove a user from a blog.
wp-includes/class-wp-comment-query.php: WP_Comment_Query::get_comment_ids()

Used internally to get a list of comment IDs matching the query vars.
wp-includes/taxonomy.php: wp_delete_term()

Removes a term from the database.
wp-includes/taxonomy.php: wp_set_object_terms()

Create Term and Taxonomy Relationships.
wp-includes/taxonomy.php: get_objects_in_term()

Retrieve object_ids of valid taxonomy and term.
wp-includes/functions.php: do_enclose()

Check content for video and audio links to add as enclosures.
wp-admin/includes/deprecated.php: WP_User_Search::query()

Executes the user search query.
wp-admin/includes/deprecated.php: get_author_user_ids()

Get all user IDs.
wp-admin/includes/deprecated.php: get_editable_user_ids()

Gets the IDs of any users who can edit posts.
wp-admin/includes/deprecated.php: get_nonauthor_user_ids()

Gets all users who are not authors.
wp-admin/includes/template.php: meta_form()

Prints the form in the Custom Fields meta box.
wp-admin/includes/schema.php: populate_options()

Create ClassicPress options and set the default values.
wp-admin/includes/nav-menu.php: _wp_delete_orphaned_draft_menu_items()

Deletes orphaned draft menu items
wp-admin/includes/class-wp-ms-users-list-table.php: WP_MS_Users_List_Table::prepare_items()
wp-admin/includes/user.php: wp_delete_user()

Remove user and optionally reassign posts and links to another user.
wp-admin/includes/export.php: export_wp()

Generates the WXR export file for download.
wp-admin/includes/class-wp-ms-sites-list-table.php: WP_MS_Sites_List_Table::prepare_items()

Prepares the list of sites for display.
wp-admin/includes/post.php: get_available_post_mime_types()

Get all available post MIME types for a given post type.
wp-admin/includes/post.php: get_meta_keys()

Get a list of previously defined keys.
wp-admin/includes/ms.php: wpmu_delete_user()

Delete a user from the network and remove from all sites.
wp-admin/includes/upgrade.php: maybe_create_table()

Creates a table in the database if it doesn’t already exist.
wp-admin/includes/upgrade.php: maybe_add_column()

Adds column to a database table if it doesn’t already exist.
wp-admin/install-helper.php: maybe_drop_column()

Drop column from database table, if it exists.
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Changelog

Changelog
Version Description
WP-0.71 Introduced.