WP_User_Query::prepare_query( string|array $query = array() )

	public function prepare_query( $query = array() ) {
		global $wpdb;

		if ( empty( $this->query_vars ) || ! empty( $query ) ) {
			$this->query_limit = null;
			$this->query_vars = $this->fill_query_vars( $query );
		}

		/**
		 * Fires before the WP_User_Query has been parsed.
		 *
		 * The passed WP_User_Query object contains the query variables, not
		 * yet passed into SQL.
		 *
		 * @since WP-4.0.0
		 *
		 * @param WP_User_Query $this The current WP_User_Query instance,
		 *                            passed by reference.
		 */
		do_action( 'pre_get_users', $this );

		// Ensure that query vars are filled after 'pre_get_users'.
		$qv =& $this->query_vars;
		$qv =  $this->fill_query_vars( $qv );

		if ( is_array( $qv['fields'] ) ) {
			$qv['fields'] = array_unique( $qv['fields'] );

			$this->query_fields = array();
			foreach ( $qv['fields'] as $field ) {
				$field = 'ID' === $field ? 'ID' : sanitize_key( $field );
				$this->query_fields[] = "$wpdb->users.$field";
			}
			$this->query_fields = implode( ',', $this->query_fields );
		} elseif ( 'all' == $qv['fields'] ) {
			$this->query_fields = "$wpdb->users.*";
		} else {
			$this->query_fields = "$wpdb->users.ID";
		}

		if ( isset( $qv['count_total'] ) && $qv['count_total'] )
			$this->query_fields = 'SQL_CALC_FOUND_ROWS ' . $this->query_fields;

		$this->query_from = "FROM $wpdb->users";
		$this->query_where = "WHERE 1=1";

		// Parse and sanitize 'include', for use by 'orderby' as well as 'include' below.
		if ( ! empty( $qv['include'] ) ) {
			$include = wp_parse_id_list( $qv['include'] );
		} else {
			$include = false;
		}

		$blog_id = 0;
		if ( isset( $qv['blog_id'] ) ) {
			$blog_id = absint( $qv['blog_id'] );
		}

		if ( $qv['has_published_posts'] && $blog_id ) {
			if ( true === $qv['has_published_posts'] ) {
				$post_types = get_post_types( array( 'public' => true ) );
			} else {
				$post_types = (array) $qv['has_published_posts'];
			}

			foreach ( $post_types as &$post_type ) {
				$post_type = $wpdb->prepare( '%s', $post_type );
			}

			$posts_table = $wpdb->get_blog_prefix( $blog_id ) . 'posts';
			$this->query_where .= " AND $wpdb->users.ID IN ( SELECT DISTINCT $posts_table.post_author FROM $posts_table WHERE $posts_table.post_status = 'publish' AND $posts_table.post_type IN ( " . join( ", ", $post_types ) . " ) )";
		}

		// nicename
		if ( '' !== $qv['nicename']) {
			$this->query_where .= $wpdb->prepare( ' AND user_nicename = %s', $qv['nicename'] );
		}

		if ( ! empty( $qv['nicename__in'] ) ) {
			$sanitized_nicename__in = array_map( 'esc_sql', $qv['nicename__in'] );
			$nicename__in = implode( "','", $sanitized_nicename__in );
			$this->query_where .= " AND user_nicename IN ( '$nicename__in' )";
		}

		if ( ! empty( $qv['nicename__not_in'] ) ) {
			$sanitized_nicename__not_in = array_map( 'esc_sql', $qv['nicename__not_in'] );
			$nicename__not_in = implode( "','", $sanitized_nicename__not_in );
			$this->query_where .= " AND user_nicename NOT IN ( '$nicename__not_in' )";
		}

		// login
		if ( '' !== $qv['login']) {
			$this->query_where .= $wpdb->prepare( ' AND user_login = %s', $qv['login'] );
		}

		if ( ! empty( $qv['login__in'] ) ) {
			$sanitized_login__in = array_map( 'esc_sql', $qv['login__in'] );
			$login__in = implode( "','", $sanitized_login__in );
			$this->query_where .= " AND user_login IN ( '$login__in' )";
		}

		if ( ! empty( $qv['login__not_in'] ) ) {
			$sanitized_login__not_in = array_map( 'esc_sql', $qv['login__not_in'] );
			$login__not_in = implode( "','", $sanitized_login__not_in );
			$this->query_where .= " AND user_login NOT IN ( '$login__not_in' )";
		}

		// Meta query.
		$this->meta_query = new WP_Meta_Query();
		$this->meta_query->parse_query_vars( $qv );

		if ( isset( $qv['who'] ) && 'authors' == $qv['who'] && $blog_id ) {
			$who_query = array(
				'key' => $wpdb->get_blog_prefix( $blog_id ) . 'user_level',
				'value' => 0,
				'compare' => '!=',
			);

			// Prevent extra meta query.
			$qv['blog_id'] = $blog_id = 0;

			if ( empty( $this->meta_query->queries ) ) {
				$this->meta_query->queries = array( $who_query );
			} else {
				// Append the cap query to the original queries and reparse the query.
				$this->meta_query->queries = array(
					'relation' => 'AND',
					array( $this->meta_query->queries, $who_query ),
				);
			}

			$this->meta_query->parse_query_vars( $this->meta_query->queries );
		}

		$roles = array();
		if ( isset( $qv['role'] ) ) {
			if ( is_array( $qv['role'] ) ) {
				$roles = $qv['role'];
			} elseif ( is_string( $qv['role'] ) && ! empty( $qv['role'] ) ) {
				$roles = array_map( 'trim', explode( ',', $qv['role'] ) );
			}
		}

		$role__in = array();
		if ( isset( $qv['role__in'] ) ) {
			$role__in = (array) $qv['role__in'];
		}

		$role__not_in = array();
		if ( isset( $qv['role__not_in'] ) ) {
			$role__not_in = (array) $qv['role__not_in'];
		}

		if ( $blog_id && ( ! empty( $roles ) || ! empty( $role__in ) || ! empty( $role__not_in ) || is_multisite() ) ) {
			$role_queries  = array();

			$roles_clauses = array( 'relation' => 'AND' );
			if ( ! empty( $roles ) ) {
				foreach ( $roles as $role ) {
					$roles_clauses[] = array(
						'key'     => $wpdb->get_blog_prefix( $blog_id ) . 'capabilities',
						'value'   => '"' . $role . '"',
						'compare' => 'LIKE',
					);
				}

				$role_queries[] = $roles_clauses;
			}

			$role__in_clauses = array( 'relation' => 'OR' );
			if ( ! empty( $role__in ) ) {
				foreach ( $role__in as $role ) {
					$role__in_clauses[] = array(
						'key'     => $wpdb->get_blog_prefix( $blog_id ) . 'capabilities',
						'value'   => '"' . $role . '"',
						'compare' => 'LIKE',
					);
				}

				$role_queries[] = $role__in_clauses;
			}

			$role__not_in_clauses = array( 'relation' => 'AND' );
			if ( ! empty( $role__not_in ) ) {
				foreach ( $role__not_in as $role ) {
					$role__not_in_clauses[] = array(
						'key'     => $wpdb->get_blog_prefix( $blog_id ) . 'capabilities',
						'value'   => '"' . $role . '"',
						'compare' => 'NOT LIKE',
					);
				}

				$role_queries[] = $role__not_in_clauses;
			}

			// If there are no specific roles named, make sure the user is a member of the site.
			if ( empty( $role_queries ) ) {
				$role_queries[] = array(
					'key' => $wpdb->get_blog_prefix( $blog_id ) . 'capabilities',
					'compare' => 'EXISTS',
				);
			}

			// Specify that role queries should be joined with AND.
			$role_queries['relation'] = 'AND';

			if ( empty( $this->meta_query->queries ) ) {
				$this->meta_query->queries = $role_queries;
			} else {
				// Append the cap query to the original queries and reparse the query.
				$this->meta_query->queries = array(
					'relation' => 'AND',
					array( $this->meta_query->queries, $role_queries ),
				);
			}

			$this->meta_query->parse_query_vars( $this->meta_query->queries );
		}

		if ( ! empty( $this->meta_query->queries ) ) {
			$clauses = $this->meta_query->get_sql( 'user', $wpdb->users, 'ID', $this );
			$this->query_from .= $clauses['join'];
			$this->query_where .= $clauses['where'];

			if ( $this->meta_query->has_or_relation() ) {
				$this->query_fields = 'DISTINCT ' . $this->query_fields;
			}
		}

		// sorting
		$qv['order'] = isset( $qv['order'] ) ? strtoupper( $qv['order'] ) : '';
		$order = $this->parse_order( $qv['order'] );

		if ( empty( $qv['orderby'] ) ) {
			// Default order is by 'user_login'.
			$ordersby = array( 'user_login' => $order );
		} elseif ( is_array( $qv['orderby'] ) ) {
			$ordersby = $qv['orderby'];
		} else {
			// 'orderby' values may be a comma- or space-separated list.
			$ordersby = preg_split( '/[,\s]+/', $qv['orderby'] );
		}

		$orderby_array = array();
		foreach ( $ordersby as $_key => $_value ) {
			if ( ! $_value ) {
				continue;
			}

			if ( is_int( $_key ) ) {
				// Integer key means this is a flat array of 'orderby' fields.
				$_orderby = $_value;
				$_order = $order;
			} else {
				// Non-integer key means this the key is the field and the value is ASC/DESC.
				$_orderby = $_key;
				$_order = $_value;
			}

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

			if ( ! $parsed ) {
				continue;
			}

			if ( 'nicename__in' === $_orderby || 'login__in' === $_orderby ) {
				$orderby_array[] = $parsed;
			} else {
				$orderby_array[] = $parsed . ' ' . $this->parse_order( $_order );
			}
		}

		// If no valid clauses were found, order by user_login.
		if ( empty( $orderby_array ) ) {
			$orderby_array[] = "user_login $order";
		}

		$this->query_orderby = 'ORDER BY ' . implode( ', ', $orderby_array );

		// limit
		if ( isset( $qv['number'] ) && $qv['number'] > 0 ) {
			if ( $qv['offset'] ) {
				$this->query_limit = $wpdb->prepare("LIMIT %d, %d", $qv['offset'], $qv['number']);
			} else {
				$this->query_limit = $wpdb->prepare( "LIMIT %d, %d", $qv['number'] * ( $qv['paged'] - 1 ), $qv['number'] );
			}
		}

		$search = '';
		if ( isset( $qv['search'] ) )
			$search = trim( $qv['search'] );

		if ( $search ) {
			$leading_wild = ( ltrim($search, '*') != $search );
			$trailing_wild = ( rtrim($search, '*') != $search );
			if ( $leading_wild && $trailing_wild )
				$wild = 'both';
			elseif ( $leading_wild )
				$wild = 'leading';
			elseif ( $trailing_wild )
				$wild = 'trailing';
			else
				$wild = false;
			if ( $wild )
				$search = trim($search, '*');

			$search_columns = array();
			if ( $qv['search_columns'] ) {
				$search_columns = array_intersect( $qv['search_columns'], array( 'ID', 'user_login', 'user_email', 'user_url', 'user_nicename', 'display_name' ) );
			}
			if ( ! $search_columns ) {
				if ( false !== strpos( $search, '@') )
					$search_columns = array('user_email');
				elseif ( is_numeric($search) )
					$search_columns = array('user_login', 'ID');
				elseif ( preg_match('|^https?://|', $search) && ! ( is_multisite() && wp_is_large_network( 'users' ) ) )
					$search_columns = array('user_url');
				else
					$search_columns = array('user_login', 'user_url', 'user_email', 'user_nicename', 'display_name');
			}

			/**
			 * Filters the columns to search in a WP_User_Query search.
			 *
			 * The default columns depend on the search term, and include 'user_email',
			 * 'user_login', 'ID', 'user_url', 'display_name', and 'user_nicename'.
			 *
			 * @since WP-3.6.0
			 *
			 * @param array         $search_columns Array of column names to be searched.
			 * @param string        $search         Text being searched.
			 * @param WP_User_Query $this           The current WP_User_Query instance.
			 */
			$search_columns = apply_filters( 'user_search_columns', $search_columns, $search, $this );

			$this->query_where .= $this->get_search_sql( $search, $search_columns, $wild );
		}

		if ( ! empty( $include ) ) {
			// Sanitized earlier.
			$ids = implode( ',', $include );
			$this->query_where .= " AND $wpdb->users.ID IN ($ids)";
		} elseif ( ! empty( $qv['exclude'] ) ) {
			$ids = implode( ',', wp_parse_id_list( $qv['exclude'] ) );
			$this->query_where .= " AND $wpdb->users.ID NOT IN ($ids)";
		}

		// Date queries are allowed for the user_registered field.
		if ( ! empty( $qv['date_query'] ) && is_array( $qv['date_query'] ) ) {
			$date_query = new WP_Date_Query( $qv['date_query'], 'user_registered' );
			$this->query_where .= $date_query->get_sql();
		}

		/**
		 * Fires after the WP_User_Query has been parsed, and before
		 * the query is executed.
		 *
		 * The passed WP_User_Query object contains SQL parts formed
		 * from parsing the given query.
		 *
		 * @since WP-3.1.0
		 *
		 * @param WP_User_Query $this The current WP_User_Query instance,
		 *                            passed by reference.
		 */
		do_action_ref_array( 'pre_user_query', array( &$this ) );
	}