查询每个月的月份的统计量，空月份填充0

$sql = "select t1.m as '月份' ,IFNULL( t2.page_view, 0 ) as '资金' from
            (
                select concat((select year(now())),'01') as m
                union select concat((select year(now())),'02')
                union select concat((select year(now())),'03')
                union select concat((select year(now())),'04')
                union select concat((select year(now())),'05')
                union select concat((select year(now())),'06')
                union select concat((select year(now())),'07')
                union select concat((select year(now())),'08')
                union select concat((select year(now())),'09')
                union select concat((select year(now())),'10')
                union select concat((select year(now())),'11')
                union select concat((select year(now())),'12')
            ) t1  
        left join 
            (
                SELECT
                    SUM( `arrival_amount` ) AS page_view,
                    FROM_UNIXTIME( createtime, '%Y%m' ) AS m 
                FROM
                    `fa_project` 
                WHERE
                    ( `createtime` BETWEEN $start_time AND $end_time $where ) 
                    AND `fa_project`.`deletetime` IS NULL 
                GROUP BY
                `m` 
            ) t2  
        on t1.m = t2.m ORDER BY t1.m ASC";