生成最近24小时整点

SELECT
    -- 每向下推1行, @i比上次减去1
		b.*, i.*,
		DATE_FORMAT( DATE_SUB( NOW(), INTERVAL ( -( @i := @i - 1 ) ) HOUR ), '%Y-%m-%d %H:00' ) AS 'time' 
FROM
	   -- 目的是生成12行数据
		( SELECT
			a 
		  FROM
			( SELECT '1' AS a UNION SELECT '2' UNION SELECT '3' UNION SELECT '4' ) AS a
			JOIN ( SELECT '1' UNION SELECT '2' UNION SELECT '3' UNION SELECT '4' UNION SELECT '5' UNION SELECT '6' ) AS b ON 1 
		) AS b,
		-- 先给1个默认的值
		( SELECT @i := 1 ) AS i -- 每次跟主表连接1次, 都会动态计算列select中的值（就跟2张普通的表按条件连接起来,然后取表中的字段一样,只不过这里取的是@i,而@i属于会话变量而已）
-- ORDER BY time 

生成最近30天

同理，往前推30天

SELECT
		DATE_FORMAT( DATE_SUB( NOW(), INTERVAL ( -( @i := @i - 1 ) ) DAY ), '%Y-%m-%d' ) AS 'time' 
FROM
	(
		SELECT
			a 
		FROM
			( SELECT '1' AS a UNION SELECT '2' UNION SELECT '3' UNION SELECT '4' UNION SELECT '5' ) AS a
			JOIN 
			( SELECT '1' UNION SELECT '2' UNION SELECT '3' UNION SELECT '4' UNION SELECT '5' UNION SELECT '6' ) AS b ON 1 
	) AS b,
	( SELECT @i := 1 ) AS i 
ORDER BY time 

生成12个月

SELECT DATE_FORMAT(CURDATE(), '%m') AS `month`
UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 1 MONTH), '%m') AS `month`
UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 2 MONTH), '%m') AS `month`
UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 3 MONTH), '%m') AS `month`
UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 4 MONTH), '%m') AS `month`
UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 5 MONTH), '%m') AS `month`
UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 6 MONTH), '%m') AS `month`
UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 7 MONTH), '%m') AS `month`
UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 8 MONTH), '%m') AS `month`
UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 9 MONTH), '%m') AS `month`
UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 10 MONTH), '%m') AS `month`
UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 11 MONTH), '%m') AS `month`