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wpdb::get_col()

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

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Retrieves 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, the column specified is returned.
If $query is null, the specified column from the previous SQL result is returned.

Parameters

$querystring|nulloptional
SQL query. Defaults to previous query.

Default:null

$xintoptional
Column to return. Indexed from 0. Default 0.

Return

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

Source

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

		$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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UsesDescription
wpdb::check_safe_collation()wp-includes/class-wpdb.php

Checks if the query is accessing a collation considered safe on the current version of MySQL.

wpdb::query()wp-includes/class-wpdb.php

Performs a database query, using current database connection.

wpdb::get_var()wp-includes/class-wpdb.php

Retrieves one value from the database.

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Used byDescription
wp_set_option_autoload_values()wp-includes/option.php

Sets the autoload values for multiple options in the database.

_wp_batch_update_comment_type()wp-includes/comment.php

Updates the comment type for a batch of comments.

wp_delete_site()wp-includes/ms-site.php

Deletes a site from the database.

WP_Network_Query::get_network_ids()wp-includes/class-wp-network-query.php

Used internally to get a list of network IDs matching the query vars.

WP_Site_Query::get_site_ids()wp-includes/class-wp-site-query.php

Used internally to get a list of site IDs matching the query vars.

wp_get_users_with_no_role()wp-includes/user.php

Gets the user IDs of all users with no role on this site.

WP_Comment_Query::get_comment_ids()wp-includes/class-wp-comment-query.php

Used internally to get a list of comment IDs matching the query vars.

maybe_drop_column()wp-admin/install-helper.php

Drops column from database table, if it exists.

WP_User_Search::query()wp-admin/includes/deprecated.php

Executes the user search query.

get_author_user_ids()wp-admin/includes/deprecated.php

Get all user IDs.

get_editable_user_ids()wp-admin/includes/deprecated.php

Gets the IDs of any users who can edit posts.

get_nonauthor_user_ids()wp-admin/includes/deprecated.php

Gets all users who are not authors.

wpmu_delete_user()wp-admin/includes/ms.php

Deletes a user and all of their posts from the network.

populate_options()wp-admin/includes/schema.php

Create WordPress options and set the default values.

maybe_create_table()wp-admin/includes/upgrade.php

Creates a table in the database, if it doesn’t already exist.

maybe_add_column()wp-admin/includes/upgrade.php

Adds column to a database table, if it doesn’t already exist.

wp_delete_user()wp-admin/includes/user.php

Delete user and optionally reassign posts and links to another user.

meta_form()wp-admin/includes/template.php

Prints the form in the Custom Fields meta box.

WP_MS_Sites_List_Table::prepare_items()wp-admin/includes/class-wp-ms-sites-list-table.php

Prepares the list of sites for display.

get_meta_keys()wp-admin/includes/post.php

Returns a list of previously defined keys.

get_available_post_mime_types()wp-includes/post.php

Gets all available post MIME types for a given post type.

_wp_delete_orphaned_draft_menu_items()wp-admin/includes/nav-menu.php

Deletes orphaned draft menu items

get_usermeta()wp-includes/deprecated.php

Retrieve user metadata.

WP_Query::get_posts()wp-includes/class-wp-query.php

Retrieves an array of posts based on query variables.

do_enclose()wp-includes/functions.php

Checks content for video and audio links to add as enclosures.

wp_set_object_terms()wp-includes/taxonomy.php

Creates term and taxonomy relationships.

wp_delete_term()wp-includes/taxonomy.php

Removes a term from the database.

get_objects_in_term()wp-includes/taxonomy.php

Retrieves object IDs of valid taxonomy and term.

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

Executes the query, with the current variables.

count_users()wp-includes/user.php

Counts number of users who have each of the user roles.

wp_delete_auto_drafts()wp-includes/post.php

Deletes auto-drafts for new posts that are > 7 days old.

wp_delete_attachment()wp-includes/post.php

Trashes or deletes an attachment.

get_all_page_ids()wp-includes/post.php

Gets a list of page IDs.

wp_delete_post()wp-includes/post.php

Trashes or deletes a post or page.

remove_user_from_blog()wp-includes/ms-functions.php

Removes a user from a blog.

is_multi_author()wp-includes/author-template.php

Determines whether this site has more than one author.

wp_delete_comment()wp-includes/comment.php

Trashes or deletes a comment.

delete_metadata()wp-includes/meta.php

Deletes metadata for the specified object.

update_metadata()wp-includes/meta.php

Updates metadata for the specified object. If no value already exists for the specified object ID and metadata key, the metadata will be added.

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Changelog

VersionDescription
0.71Introduced.

User Contributed Notes

  1. Skip to note 2 content
    Big-Erny
    You must log in to vote on the helpfulness of this noteVote results for this note: 6You must log in to vote on the helpfulness of this note
    global $wpdb;

$table_name = $wpdb->prefix . 'some_custom_table_name';

$field_name = 'some_field';
$user_id = get_current_user_id();

$prepared_statement = $wpdb->prepare( "SELECT {$field_name} FROM {$table_name} WHERE  user_id = %d", $user_id );
$values = $wpdb->get_col( $prepared_statement );

    Returns an array of $field_name values in the $table_name that match the $user_id

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