Sql 查询近几天、近几个月数据没有补0

SELECt
	dc._date AS date,
	IFNULL( ccd.newsCount, 0 ) AS newsCount 
FROM
	(
	SELECt
		@s := @s + 1 AS _index,
		DATE( DATE_SUB( CURRENT_DATE, INTERVAL @s DAY ) ) AS _date 
		FROM
		# 关联任意一张系统表; 一定的是系统表;
		mysql.help_topic,
		( SELECt @s := - 1 ) temp 
	WHERe
		@s < 6 
	ORDER BY
		_date 
	) AS dc
	LEFT JOIN (
	SELECT
		count( 1 ) AS newsCount,
		DATE( c.create_time ) createdate 
	FROM
		`content` c 
	WHERe
		c.org_id = '888888888' 
		AND c.dept_id = '1' 
	GROUP BY
		createdate 
	) AS ccd ON dc._date = ccd.createdate 
GROUP BY
	dc._date

月份

SELECt ConVERT
	( t2.year_month_str, CHAR ) `month`,
	IFNULL( ccd.newsCount, 0 ) AS newsCount 
FROM
	(
	SELECt
		@rownum := @rownum + 1 AS num,
		date_format( DATE_SUB( now(), INTERVAL @rownum MonTH ), '%Y-%m' ) AS year_month_str 
	FROM
		( SELECt @rownum := - 1 ) AS r_init,
		( SELECT c.help_topic_id FROM mysql.help_topic c LIMIT 12 ) AS c_init 
	) t2
	LEFT JOIN (
	SELECt
		count( 1 ) AS newsCount,
		CONCAt( DATE_FORMAT( c.create_time, '%Y' ), '-', DATE_FORMAT( c.create_time, '%m' ) ) createdate 
	FROM
		`content` c 
	WHERe
		c.org_id = '88888' 
		AND c.dept_id = '1' 
	GROUP BY
		createdate 
	) ccd ON ccd.createdate = t2.year_month_str 
GROUP BY
	t2.year_month_str