WP_Term_Query::get_terms(): WP_Term[]|int[]|string[]|string

Retrieves the query results.


Description

The return type varies depending on the value passed to $args['fields'].

The following will result in an array of WP_Term objects being returned:

  • ‘all’
  • ‘all_with_object_id’

The following will result in a numeric string being returned:

  • ‘count’

The following will result in an array of text strings being returned:

  • ‘id=>name’
  • ‘id=>slug’
  • ‘names’
  • ‘slugs’

The following will result in an array of numeric strings being returned:

  • ‘id=>parent’

The following will result in an array of integers being returned:

  • ‘ids’
  • ‘tt_ids’

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Return

WP_Term[]|int[]|string[]|string Array of terms, or number of terms as numeric string when 'count' is passed as a query var.


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Source

File: wp-includes/class-wp-term-query.php. View all references

public function get_terms() {
	global $wpdb;

	$this->parse_query( $this->query_vars );
	$args = &$this->query_vars;

	// Set up meta_query so it's available to 'pre_get_terms'.
	$this->meta_query = new WP_Meta_Query();
	$this->meta_query->parse_query_vars( $args );

	/**
	 * Fires before terms are retrieved.
	 *
	 * @since 4.6.0
	 *
	 * @param WP_Term_Query $query Current instance of WP_Term_Query (passed by reference).
	 */
	do_action_ref_array( 'pre_get_terms', array( &$this ) );

	$taxonomies = (array) $args['taxonomy'];

	// Save queries by not crawling the tree in the case of multiple taxes or a flat tax.
	$has_hierarchical_tax = false;
	if ( $taxonomies ) {
		foreach ( $taxonomies as $_tax ) {
			if ( is_taxonomy_hierarchical( $_tax ) ) {
				$has_hierarchical_tax = true;
			}
		}
	} else {
		// When no taxonomies are provided, assume we have to descend the tree.
		$has_hierarchical_tax = true;
	}

	if ( ! $has_hierarchical_tax ) {
		$args['hierarchical'] = false;
		$args['pad_counts']   = false;
	}

	// 'parent' overrides 'child_of'.
	if ( 0 < (int) $args['parent'] ) {
		$args['child_of'] = false;
	}

	if ( 'all' === $args['get'] ) {
		$args['childless']    = false;
		$args['child_of']     = 0;
		$args['hide_empty']   = 0;
		$args['hierarchical'] = false;
		$args['pad_counts']   = false;
	}

	/**
	 * Filters the terms query arguments.
	 *
	 * @since 3.1.0
	 *
	 * @param array    $args       An array of get_terms() arguments.
	 * @param string[] $taxonomies An array of taxonomy names.
	 */
	$args = apply_filters( 'get_terms_args', $args, $taxonomies );

	// Avoid the query if the queried parent/child_of term has no descendants.
	$child_of = $args['child_of'];
	$parent   = $args['parent'];

	if ( $child_of ) {
		$_parent = $child_of;
	} elseif ( $parent ) {
		$_parent = $parent;
	} else {
		$_parent = false;
	}

	if ( $_parent ) {
		$in_hierarchy = false;
		foreach ( $taxonomies as $_tax ) {
			$hierarchy = _get_term_hierarchy( $_tax );

			if ( isset( $hierarchy[ $_parent ] ) ) {
				$in_hierarchy = true;
			}
		}

		if ( ! $in_hierarchy ) {
			if ( 'count' === $args['fields'] ) {
				return 0;
			} else {
				$this->terms = array();
				return $this->terms;
			}
		}
	}

	// 'term_order' is a legal sort order only when joining the relationship table.
	$_orderby = $this->query_vars['orderby'];
	if ( 'term_order' === $_orderby && empty( $this->query_vars['object_ids'] ) ) {
		$_orderby = 'term_id';
	}

	$orderby = $this->parse_orderby( $_orderby );

	if ( $orderby ) {
		$orderby = "ORDER BY $orderby";
	}

	$order = $this->parse_order( $this->query_vars['order'] );

	if ( $taxonomies ) {
		$this->sql_clauses['where']['taxonomy'] =
			"tt.taxonomy IN ('" . implode( "', '", array_map( 'esc_sql', $taxonomies ) ) . "')";
	}

	if ( empty( $args['exclude'] ) ) {
		$args['exclude'] = array();
	}

	if ( empty( $args['include'] ) ) {
		$args['include'] = array();
	}

	$exclude      = $args['exclude'];
	$exclude_tree = $args['exclude_tree'];
	$include      = $args['include'];

	$inclusions = '';
	if ( ! empty( $include ) ) {
		$exclude      = '';
		$exclude_tree = '';
		$inclusions   = implode( ',', wp_parse_id_list( $include ) );
	}

	if ( ! empty( $inclusions ) ) {
		$this->sql_clauses['where']['inclusions'] = 't.term_id IN ( ' . $inclusions . ' )';
	}

	$exclusions = array();
	if ( ! empty( $exclude_tree ) ) {
		$exclude_tree      = wp_parse_id_list( $exclude_tree );
		$excluded_children = $exclude_tree;
		foreach ( $exclude_tree as $extrunk ) {
			$excluded_children = array_merge(
				$excluded_children,
				(array) get_terms(
					array(
						'taxonomy'   => reset( $taxonomies ),
						'child_of'   => (int) $extrunk,
						'fields'     => 'ids',
						'hide_empty' => 0,
					)
				)
			);
		}
		$exclusions = array_merge( $excluded_children, $exclusions );
	}

	if ( ! empty( $exclude ) ) {
		$exclusions = array_merge( wp_parse_id_list( $exclude ), $exclusions );
	}

	// 'childless' terms are those without an entry in the flattened term hierarchy.
	$childless = (bool) $args['childless'];
	if ( $childless ) {
		foreach ( $taxonomies as $_tax ) {
			$term_hierarchy = _get_term_hierarchy( $_tax );
			$exclusions     = array_merge( array_keys( $term_hierarchy ), $exclusions );
		}
	}

	if ( ! empty( $exclusions ) ) {
		$exclusions = 't.term_id NOT IN (' . implode( ',', array_map( 'intval', $exclusions ) ) . ')';
	} else {
		$exclusions = '';
	}

	/**
	 * Filters the terms to exclude from the terms query.
	 *
	 * @since 2.3.0
	 *
	 * @param string   $exclusions `NOT IN` clause of the terms query.
	 * @param array    $args       An array of terms query arguments.
	 * @param string[] $taxonomies An array of taxonomy names.
	 */
	$exclusions = apply_filters( 'list_terms_exclusions', $exclusions, $args, $taxonomies );

	if ( ! empty( $exclusions ) ) {
		// Must do string manipulation here for backward compatibility with filter.
		$this->sql_clauses['where']['exclusions'] = preg_replace( '/^\s*AND\s*/', '', $exclusions );
	}

	if ( '' === $args['name'] ) {
		$args['name'] = array();
	} else {
		$args['name'] = (array) $args['name'];
	}

	if ( ! empty( $args['name'] ) ) {
		$names = $args['name'];
		foreach ( $names as &$_name ) {
			// `sanitize_term_field()` returns slashed data.
			$_name = stripslashes( sanitize_term_field( 'name', $_name, 0, reset( $taxonomies ), 'db' ) );
		}

		$this->sql_clauses['where']['name'] = "t.name IN ('" . implode( "', '", array_map( 'esc_sql', $names ) ) . "')";
	}

	if ( '' === $args['slug'] ) {
		$args['slug'] = array();
	} else {
		$args['slug'] = array_map( 'sanitize_title', (array) $args['slug'] );
	}

	if ( ! empty( $args['slug'] ) ) {
		$slug = implode( "', '", $args['slug'] );

		$this->sql_clauses['where']['slug'] = "t.slug IN ('" . $slug . "')";
	}

	if ( '' === $args['term_taxonomy_id'] ) {
		$args['term_taxonomy_id'] = array();
	} else {
		$args['term_taxonomy_id'] = array_map( 'intval', (array) $args['term_taxonomy_id'] );
	}

	if ( ! empty( $args['term_taxonomy_id'] ) ) {
		$tt_ids = implode( ',', $args['term_taxonomy_id'] );

		$this->sql_clauses['where']['term_taxonomy_id'] = "tt.term_taxonomy_id IN ({$tt_ids})";
	}

	if ( ! empty( $args['name__like'] ) ) {
		$this->sql_clauses['where']['name__like'] = $wpdb->prepare(
			't.name LIKE %s',
			'%' . $wpdb->esc_like( $args['name__like'] ) . '%'
		);
	}

	if ( ! empty( $args['description__like'] ) ) {
		$this->sql_clauses['where']['description__like'] = $wpdb->prepare(
			'tt.description LIKE %s',
			'%' . $wpdb->esc_like( $args['description__like'] ) . '%'
		);
	}

	if ( '' === $args['object_ids'] ) {
		$args['object_ids'] = array();
	} else {
		$args['object_ids'] = array_map( 'intval', (array) $args['object_ids'] );
	}

	if ( ! empty( $args['object_ids'] ) ) {
		$object_ids = implode( ', ', $args['object_ids'] );

		$this->sql_clauses['where']['object_ids'] = "tr.object_id IN ($object_ids)";
	}

	/*
	 * When querying for object relationships, the 'count > 0' check
	 * added by 'hide_empty' is superfluous.
	 */
	if ( ! empty( $args['object_ids'] ) ) {
		$args['hide_empty'] = false;
	}

	if ( '' !== $parent ) {
		$parent                               = (int) $parent;
		$this->sql_clauses['where']['parent'] = "tt.parent = '$parent'";
	}

	$hierarchical = $args['hierarchical'];
	if ( 'count' === $args['fields'] ) {
		$hierarchical = false;
	}
	if ( $args['hide_empty'] && ! $hierarchical ) {
		$this->sql_clauses['where']['count'] = 'tt.count > 0';
	}

	$number = $args['number'];
	$offset = $args['offset'];

	// Don't limit the query results when we have to descend the family tree.
	if ( $number && ! $hierarchical && ! $child_of && '' === $parent ) {
		if ( $offset ) {
			$limits = 'LIMIT ' . $offset . ',' . $number;
		} else {
			$limits = 'LIMIT ' . $number;
		}
	} else {
		$limits = '';
	}

	if ( ! empty( $args['search'] ) ) {
		$this->sql_clauses['where']['search'] = $this->get_search_sql( $args['search'] );
	}

	// Meta query support.
	$join     = '';
	$distinct = '';

	// Reparse meta_query query_vars, in case they were modified in a 'pre_get_terms' callback.
	$this->meta_query->parse_query_vars( $this->query_vars );
	$mq_sql       = $this->meta_query->get_sql( 'term', 't', 'term_id' );
	$meta_clauses = $this->meta_query->get_clauses();

	if ( ! empty( $meta_clauses ) ) {
		$join                                    .= $mq_sql['join'];
		$this->sql_clauses['where']['meta_query'] = preg_replace( '/^\s*AND\s*/', '', $mq_sql['where'] );
		$distinct                                .= 'DISTINCT';

	}

	$selects = array();
	switch ( $args['fields'] ) {
		case 'count':
			$orderby = '';
			$order   = '';
			$selects = array( 'COUNT(*)' );
			break;
		default:
			$selects = array( 't.term_id' );
			if ( 'all_with_object_id' === $args['fields'] && ! empty( $args['object_ids'] ) ) {
				$selects[] = 'tr.object_id';
			}
			break;
	}

	$_fields = $args['fields'];

	/**
	 * Filters the fields to select in the terms query.
	 *
	 * Field lists modified using this filter will only modify the term fields returned
	 * by the function when the `$fields` parameter set to 'count' or 'all'. In all other
	 * cases, the term fields in the results array will be determined by the `$fields`
	 * parameter alone.
	 *
	 * Use of this filter can result in unpredictable behavior, and is not recommended.
	 *
	 * @since 2.8.0
	 *
	 * @param string[] $selects    An array of fields to select for the terms query.
	 * @param array    $args       An array of term query arguments.
	 * @param string[] $taxonomies An array of taxonomy names.
	 */
	$fields = implode( ', ', apply_filters( 'get_terms_fields', $selects, $args, $taxonomies ) );

	$join .= " INNER JOIN $wpdb->term_taxonomy AS tt ON t.term_id = tt.term_id";

	if ( ! empty( $this->query_vars['object_ids'] ) ) {
		$join    .= " INNER JOIN {$wpdb->term_relationships} AS tr ON tr.term_taxonomy_id = tt.term_taxonomy_id";
		$distinct = 'DISTINCT';
	}

	$where = implode( ' AND ', $this->sql_clauses['where'] );

	$clauses = array( 'fields', 'join', 'where', 'distinct', 'orderby', 'order', 'limits' );

	/**
	 * Filters the terms query SQL clauses.
	 *
	 * @since 3.1.0
	 *
	 * @param string[] $clauses {
	 *     Associative array of the clauses for the query.
	 *
	 *     @type string $fields   The SELECT clause of the query.
	 *     @type string $join     The JOIN clause of the query.
	 *     @type string $where    The WHERE clause of the query.
	 *     @type string $distinct The DISTINCT clause of the query.
	 *     @type string $orderby  The ORDER BY clause of the query.
	 *     @type string $order    The ORDER clause of the query.
	 *     @type string $limits   The LIMIT clause of the query.
	 * }
	 * @param string[] $taxonomies An array of taxonomy names.
	 * @param array    $args       An array of term query arguments.
	 */
	$clauses = apply_filters( 'terms_clauses', compact( $clauses ), $taxonomies, $args );

	$fields   = isset( $clauses['fields'] ) ? $clauses['fields'] : '';
	$join     = isset( $clauses['join'] ) ? $clauses['join'] : '';
	$where    = isset( $clauses['where'] ) ? $clauses['where'] : '';
	$distinct = isset( $clauses['distinct'] ) ? $clauses['distinct'] : '';
	$orderby  = isset( $clauses['orderby'] ) ? $clauses['orderby'] : '';
	$order    = isset( $clauses['order'] ) ? $clauses['order'] : '';
	$limits   = isset( $clauses['limits'] ) ? $clauses['limits'] : '';

	if ( $where ) {
		$where = "WHERE $where";
	}

	$this->sql_clauses['select']  = "SELECT $distinct $fields";
	$this->sql_clauses['from']    = "FROM $wpdb->terms AS t $join";
	$this->sql_clauses['orderby'] = $orderby ? "$orderby $order" : '';
	$this->sql_clauses['limits']  = $limits;

	$this->request = "
		{$this->sql_clauses['select']}
		{$this->sql_clauses['from']}
		{$where}
		{$this->sql_clauses['orderby']}
		{$this->sql_clauses['limits']}
	";

	$this->terms = null;

	/**
	 * Filters the terms array before the query takes place.
	 *
	 * Return a non-null value to bypass WordPress' default term queries.
	 *
	 * @since 5.3.0
	 *
	 * @param array|null    $terms Return an array of term data to short-circuit WP's term query,
	 *                             or null to allow WP queries to run normally.
	 * @param WP_Term_Query $query The WP_Term_Query instance, passed by reference.
	 */
	$this->terms = apply_filters_ref_array( 'terms_pre_query', array( $this->terms, &$this ) );

	if ( null !== $this->terms ) {
		return $this->terms;
	}

	// $args can be anything. Only use the args defined in defaults to compute the key.
	$cache_args = wp_array_slice_assoc( $args, array_keys( $this->query_var_defaults ) );

	unset( $cache_args['update_term_meta_cache'] );

	if ( 'count' !== $_fields && 'all_with_object_id' !== $_fields ) {
		$cache_args['fields'] = 'all';
	}

	$key          = md5( serialize( $cache_args ) . serialize( $taxonomies ) . $this->request );
	$last_changed = wp_cache_get_last_changed( 'terms' );
	$cache_key    = "get_terms:$key:$last_changed";
	$cache        = wp_cache_get( $cache_key, 'terms' );

	if ( false !== $cache ) {
		if ( 'ids' === $_fields ) {
			$cache = array_map( 'intval', $cache );
		} elseif ( 'count' !== $_fields ) {
			if ( ( 'all_with_object_id' === $_fields && ! empty( $args['object_ids'] ) ) || ( 'all' === $_fields && $args['pad_counts'] ) ) {
				$term_ids = wp_list_pluck( $cache, 'term_id' );
			} else {
				$term_ids = array_map( 'intval', $cache );
			}
			_prime_term_caches( $term_ids, $args['update_term_meta_cache'] );
			$term_objects = $this->populate_terms( $cache );
			$cache        = $this->format_terms( $term_objects, $_fields );
		}

		$this->terms = $cache;
		return $this->terms;
	}

	if ( 'count' === $_fields ) {
		$count = $wpdb->get_var( $this->request ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
		wp_cache_set( $cache_key, $count, 'terms' );
		return $count;
	}

	$terms = $wpdb->get_results( $this->request ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared

	if ( empty( $terms ) ) {
		wp_cache_add( $cache_key, array(), 'terms' );
		return array();
	}

	$term_ids = wp_list_pluck( $terms, 'term_id' );
	_prime_term_caches( $term_ids, false );
	$term_objects = $this->populate_terms( $terms );

	if ( $child_of ) {
		foreach ( $taxonomies as $_tax ) {
			$children = _get_term_hierarchy( $_tax );
			if ( ! empty( $children ) ) {
				$term_objects = _get_term_children( $child_of, $term_objects, $_tax );
			}
		}
	}

	// Update term counts to include children.
	if ( $args['pad_counts'] && 'all' === $_fields ) {
		foreach ( $taxonomies as $_tax ) {
			_pad_term_counts( $term_objects, $_tax );
		}
	}

	// Make sure we show empty categories that have children.
	if ( $hierarchical && $args['hide_empty'] && is_array( $term_objects ) ) {
		foreach ( $term_objects as $k => $term ) {
			if ( ! $term->count ) {
				$children = get_term_children( $term->term_id, $term->taxonomy );
				if ( is_array( $children ) ) {
					foreach ( $children as $child_id ) {
						$child = get_term( $child_id, $term->taxonomy );
						if ( $child->count ) {
							continue 2;
						}
					}
				}

				// It really is empty.
				unset( $term_objects[ $k ] );
			}
		}
	}

	// Hierarchical queries are not limited, so 'offset' and 'number' must be handled now.
	if ( $hierarchical && $number && is_array( $term_objects ) ) {
		if ( $offset >= count( $term_objects ) ) {
			$term_objects = array();
		} else {
			$term_objects = array_slice( $term_objects, $offset, $number, true );
		}
	}

	// Prime termmeta cache.
	if ( $args['update_term_meta_cache'] ) {
		$term_ids = wp_list_pluck( $term_objects, 'term_id' );
		update_termmeta_cache( $term_ids );
	}

	if ( 'all_with_object_id' === $_fields && ! empty( $args['object_ids'] ) ) {
		$term_cache = array();
		foreach ( $term_objects as $term ) {
			$object            = new stdClass();
			$object->term_id   = $term->term_id;
			$object->object_id = $term->object_id;
			$term_cache[]      = $object;
		}
	} elseif ( 'all' === $_fields && $args['pad_counts'] ) {
		$term_cache = array();
		foreach ( $term_objects as $term ) {
			$object          = new stdClass();
			$object->term_id = $term->term_id;
			$object->count   = $term->count;
			$term_cache[]    = $object;
		}
	} else {
		$term_cache = wp_list_pluck( $term_objects, 'term_id' );
	}
	wp_cache_add( $cache_key, $term_cache, 'terms' );
	$this->terms = $this->format_terms( $term_objects, $_fields );

	return $this->terms;
}

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Hooks

apply_filters( 'get_terms_args', array $args, string[] $taxonomies )

Filters the terms query arguments.

apply_filters( 'get_terms_fields', string[] $selects, array $args, string[] $taxonomies )

Filters the fields to select in the terms query.

apply_filters( 'list_terms_exclusions', string $exclusions, array $args, string[] $taxonomies )

Filters the terms to exclude from the terms query.

do_action_ref_array( 'pre_get_terms', WP_Term_Query $query )

Fires before terms are retrieved.

apply_filters( 'terms_clauses', string[] $clauses, string[] $taxonomies, array $args )

Filters the terms query SQL clauses.

apply_filters_ref_array( 'terms_pre_query', array|null $terms, WP_Term_Query $query )

Filters the terms array before the query takes place.



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Changelog

Changelog
Version Description
4.6.0 Introduced.

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User Contributed Notes

  1. Skip to note 1 content
    Contributed by Khokan Sardar
    <ul>
    <?php 
    $args = array(
        'taxonomy'               => 'category',
        'orderby'                => 'name',
        'order'                  => 'ASC',
        'hide_empty'             => false,
    );
    $the_query = new WP_Term_Query($args);
    foreach($the_query->get_terms() as $term){ 
    ?>
    	<li><?php echo $term->name." (".$term->count.")"; ?></li>
    <?php
    }
    ?>
    </ul>

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