mysql查询当前日期的前12个月的统计

select 
ifnull(b.num,0) as sum,a.date, b.plate_number
 from 
(
SELECT DATE_FORMAT(DATE_SUB(curdate(), INTERVAL 0 MONTH), '%Y-%m') AS date UNION
SELECT DATE_FORMAT(DATE_SUB(curdate(), INTERVAL 1 MONTH), '%Y-%m') AS date UNION
SELECT DATE_FORMAT(DATE_SUB(curdate(), INTERVAL 2 MONTH), '%Y-%m') AS date UNION
SELECT DATE_FORMAT(DATE_SUB(curdate(), INTERVAL 3 MONTH), '%Y-%m') AS date UNION
SELECT DATE_FORMAT(DATE_SUB(curdate(), INTERVAL 4 MONTH), '%Y-%m') AS date UNION
SELECT DATE_FORMAT(DATE_SUB(curdate(), INTERVAL 5 MONTH), '%Y-%m') AS date UNION
SELECT DATE_FORMAT(DATE_SUB(curdate(), INTERVAL 6 MONTH), '%Y-%m') AS date UNION
SELECT DATE_FORMAT(DATE_SUB(curdate(), INTERVAL 7 MONTH), '%Y-%m') AS date UNION
SELECT DATE_FORMAT(DATE_SUB(curdate(), INTERVAL 8 MONTH), '%Y-%m') AS date UNION
SELECT DATE_FORMAT(DATE_SUB(curdate(), INTERVAL 9 MONTH), '%Y-%m') AS date UNION
SELECT DATE_FORMAT(DATE_SUB(curdate(), INTERVAL 10 MONTH), '%Y-%m') AS date UNION
SELECT DATE_FORMAT(DATE_SUB(curdate(), INTERVAL 11 MONTH), '%Y-%m') AS date
)a
left join
(select  sum(real_deliver_cargo_weight) as num,DATE_FORMAT(gmt_created, '%Y-%m') AS create_time, plate_number from waybill  group by create_time) b   
on a.date = b.create_time
ORDER BY a.date;