}

		$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'] );

		$pieces = 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( $pieces ), $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'] : '';

		$fields_is_filtered = implode( ', ', $selects ) !== $fields;

		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;

		// Beginning of the string is on a new line to prevent leading whitespace. See https://core.trac.wordpress.org/ticket/56841.
		$this->request =
			"{$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;
		}

		if ( $args['cache_results'] ) {
			$cache_key = $this->generate_cache_key( $args, $this->request );
			$cache     = wp_cache_get( $cache_key, 'term-queries' );

			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'] || $fields_is_filtered )
					) {
						$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
			if ( $args['cache_results'] ) {
				wp_cache_set( $cache_key, $count, 'term-queries' );
			}
			return $count;
		}

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

		if ( empty( $terms ) ) {
			if ( $args['cache_results'] ) {
				wp_cache_add( $cache_key, array(), 'term-queries' );
			}
			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' );
			wp_lazyload_term_meta( $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;
			}
		} elseif ( $fields_is_filtered ) {
			$term_cache = $term_objects;
		} else {
			$term_cache = wp_list_pluck( $term_objects, 'term_id' );
		}

		if ( $args['cache_results'] ) {
			wp_cache_add( $cache_key, $term_cache, 'term-queries' );
		}

		$this->terms = $this->format_terms( $term_objects, $_fields );

		return $this->terms;
	}

	/**
	 * Parse and sanitize 'orderby' keys passed to the term query.
	 *
	 * @since 4.6.0
	 *
	 * @param string $orderby_raw Alias for the field to order by.
	 * @return string|false Value to used in the ORDER clause. False otherwise.
	 */
	protected function parse_orderby( $orderby_raw ) {
		$_orderby           = strtolower( $orderby_raw );
		$maybe_orderby_meta = false;

		if ( in_array( $_orderby, array( 'term_id', 'name', 'slug', 'term_group' ), true ) ) {
			$orderby = "t.$_orderby";
		} elseif ( in_array( $_orderby, array( 'count', 'parent', 'taxonomy', 'term_taxonomy_id', 'description' ), true ) ) {
			$orderby = "tt.$_orderby";
		} elseif ( 'term_order' === $_orderby ) {
			$orderby = 'tr.term_order';
		} elseif ( 'include' === $_orderby && ! empty( $this->query_vars['include'] ) ) {
			$include = implode( ',', wp_parse_id_list( $this->query_vars['include'] ) );
			$orderby = "FIELD( t.term_id, $include )";
		} elseif ( 'slug__in' === $_orderby && ! empty( $this->query_vars['slug'] ) && is_array( $this->query_vars['slug'] ) ) {
			$slugs   = implode( "', '", array_map( 'sanitize_title_for_query', $this->query_vars['slug'] ) );
			$orderby = "FIELD( t.slug, '" . $slugs . "')";
		} elseif ( 'none' === $_orderby ) {
			$orderby = '';
		} elseif ( empty( $_orderby ) || 'id' === $_orderby || 'term_id' === $_orderby ) {
			$orderby = 't.term_id';
		} else {
			$orderby = 't.name';

			// This may be a value of orderby related to meta.
			$maybe_orderby_meta = true;
		}

		/**
		 * Filters the ORDERBY clause of the terms query.
		 *
		 * @since 2.8.0
		 *
		 * @param string   $orderby    `ORDERBY` clause of the terms query.
		 * @param array    $args       An array of term query arguments.
		 * @param string[] $taxonomies An array of taxonomy names.
		 */
		$orderby = apply_filters( 'get_terms_orderby', $orderby, $this->query_vars, $this->query_vars['taxonomy'] );

		// Run after the 'get_terms_orderby' filter for backward compatibility.
		if ( $maybe_orderby_meta ) {
			$maybe_orderby_meta = $this->parse_orderby_meta( $_orderby );
			if ( $maybe_orderby_meta ) {
				$orderby = $maybe_orderby_meta;
			}
		}

		return $orderby;
	}

	/**
	 * Format response depending on field requested.
	 *
	 * @since 6.0.0
	 *
	 * @param WP_Term[] $term_objects Array of term objects.
	 * @param string    $_fields      Field to format.
	 *
	 * @return WP_Term[]|int[]|string[] Array of terms / strings / ints depending on field requested.
	 */
	protected function format_terms( $term_objects, $_fields ) {
		$_terms = array();
		if ( 'id=>parent' === $_fields ) {
			foreach ( $term_objects as $term ) {
				$_terms[ $term->term_id ] = $term->parent;
			}
		} elseif ( 'ids' === $_fields ) {
			foreach ( $term_objects as $term ) {
				$_terms[] = (int) $term->term_id;
			}
		} elseif ( 'tt_ids' === $_fields ) {
			foreach ( $term_objects as $term ) {
				$_terms[] = (int) $term->term_taxonomy_id;
			}
		} elseif ( 'names' === $_fields ) {
			foreach ( $term_objects as $term ) {
				$_terms[] = $term->name;
			}
		} elseif ( 'slugs' === $_fields ) {
			foreach ( $term_objects as $term ) {
				$_terms[] = $term->slug;
			}
		} elseif ( 'id=>name' === $_fields ) {
			foreach ( $term_objects as $term ) {
				$_terms[ $term->term_id ] = $term->name;
			}
		} elseif ( 'id=>slug' === $_fields ) {
			foreach ( $term_objects as $term ) {
				$_terms[ $term->term_id ] = $term->slug;
			}
		} elseif ( 'all' === $_fields || 'all_with_object_id' === $_fields ) {
			$_terms = $term_objects;
		}

		return $_terms;
	}

	/**
	 * Generate the ORDER BY clause for an 'orderby' param that is potentially related to a meta query.
	 *
	 * @since 4.6.0
	 *
	 * @param string $orderby_raw Raw 'orderby' value passed to WP_Term_Query.
	 * @return string ORDER BY clause.
	 */
	protected function parse_orderby_meta( $orderby_raw ) {
		$orderby = '';

		// Tell the meta query to generate its SQL, so we have access to table aliases.
		$this->meta_query->get_sql( 'term', 't', 'term_id' );
		$meta_clauses = $this->meta_query->get_clauses();
		if ( ! $meta_clauses || ! $orderby_raw ) {
			return $orderby;
		}

		$allowed_keys       = array();
		$primary_meta_key   = null;
		$primary_meta_query = reset( $meta_clauses );
		if ( ! empty( $primary_meta_query['key'] ) ) {
			$primary_meta_key = $primary_meta_query['key'];
			$allowed_keys[]   = $primary_meta_key;
		}
		$allowed_keys[] = 'meta_value';
		$allowed_keys[] = 'meta_value_num';
		$allowed_keys   = array_merge( $allowed_keys, array_keys( $meta_clauses ) );

		if ( ! in_array( $orderby_raw, $allowed_keys, true ) ) {
			return $orderby;
		}

		switch ( $orderby_raw ) {
			case $primary_meta_key:
			case 'meta_value':
				if ( ! empty( $primary_meta_query['type'] ) ) {
					$orderby = "CAST({$primary_meta_query['alias']}.meta_value AS {$primary_meta_query['cast']})";
				} else {
					$orderby = "{$primary_meta_query['alias']}.meta_value";
				}
				break;

			case 'meta_value_num':
				$orderby = "{$primary_meta_query['alias']}.meta_value+0";
				break;

			default:
				if ( array_key_exists( $orderby_raw, $meta_clauses ) ) {
					// $orderby corresponds to a meta_query clause.
					$meta_clause = $meta_clauses[ $orderby_raw ];
					$orderby     = "CAST({$meta_clause['alias']}.meta_value AS {$meta_clause['cast']})";
				}
				break;
		}

		return $orderby;
	}

	/**
	 * Parse an 'order' query variable and cast it to ASC or DESC as necessary.
	 *
	 * @since 4.6.0
	 *
	 * @param string $order The 'order' query variable.
	 * @return string The sanitized 'order' query variable.
	 */
	protected function parse_order( $order ) {
		if ( ! is_string( $order ) || empty( $order ) ) {
			return 'DESC';
		}

		if ( 'ASC' === strtoupper( $order ) ) {
			return 'ASC';
		} else {
			return 'DESC';
		}
	}

	/**
	 * Used internally to generate a SQL string related to the 'search' parameter.
	 *
	 * @since 4.6.0
	 *
	 * @global wpdb $wpdb WordPress database abstraction object.
	 *
	 * @param string $search Search string.
	 * @return string Search SQL.
	 */
	protected function get_search_sql( $search ) {
		global $wpdb;

		$like = '%' . $wpdb->esc_like( $search ) . '%';

		return $wpdb->prepare( '((t.name LIKE %s) OR (t.slug LIKE %s))', $like, $like );
	}

	/**
	 * Creates an array of term objects from an array of term IDs.
	 *
	 * Also discards invalid term objects.
	 *
	 * @since 4.9.8
	 *
	 * @param Object[]|int[] $terms List of objects or term ids.
	 * @return WP_Term[] Array of `WP_Term` objects.
	 */
	protected function populate_terms( $terms ) {
		$term_objects = array();
		if ( ! is_array( $terms ) ) {
			return $term_objects;
		}

		foreach ( $terms as $key => $term_data ) {
			if ( is_object( $term_data ) && property_exists( $term_data, 'term_id' ) ) {
				$term = get_term( $term_data->term_id );
				if ( property_exists( $term_data, 'object_id' ) ) {
					$term->object_id = (int) $term_data->object_id;
				}
				if ( property_exists( $term_data, 'count' ) ) {
					$term->count = (int) $term_data->count;
				}
			} else {
				$term = get_term( $term_data );
			}

			if ( $term instanceof WP_Term ) {
				$term_objects[ $key ] = $term;
			}
		}

		return $term_objects;
	}

	/**
	 * Generate cache key.
	 *
	 * @since 6.2.0
	 *
	 * @global wpdb $wpdb WordPress database abstraction object.
	 *
	 * @param array  $args WP_Term_Query arguments.
	 * @param string $sql  SQL statement.
	 *
	 * @return string Cache key.
	 */
	protected function generate_cache_key( array $args, $sql ) {
		global $wpdb;
		// $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['cache_results'], $cache_args['update_term_meta_cache'] );

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

		// Replace wpdb placeholder in the SQL statement used by the cache key.
		$sql = $wpdb->remove_placeholder_escape( $sql );

		$key          = md5( serialize( $cache_args ) . $sql );
		$last_changed = wp_cache_get_last_changed( 'terms' );
		return "get_terms:$key:$last_changed";
	}
}