sql联系题（7）

-- 46、查询各学生的年龄
	-- 按照出生日期来算，当前X月Y日 < 出生年月的 月日 则，年龄减一

select s_birth,(DATE_FORMAT(NOW(),'%Y')- DATE_FORMAT(s_birth,'%Y') - 
(case when DATE_FORMAT(NOW(),'%m%d') > DATE_FORMAT(s_birth,'%m%d') then 0 else 1 end)) as age from student;

-- 47、查询本周过生日的学生
	select * from student where WEEK(DATE_FORMAT(NOW(),'%Y%m%d')) = WEEK(s_birth)
	
	select * from student where YEARWEEK(s_birth) = YEARWEEK(DATE_FORMAT(NOW(),'%Y%m%d'))
	
	select WEEK(DATE_FORMAT(NOW(),'%Y%m%d'))
	SELECT YEARWEEK(DATE_FORMAT(NOW(),'%Y%m%d'))
	SELECT month(DATE_FORMAT(NOW(),'%Y%m%d'))
	SELECT YEAR(DATE_FORMAT(NOW(),'%Y%m%d'))

-- 48、查询下周过生日的学生
	select * from student where WEEK(DATE_FORMAT(NOW(),'%Y%m%d'))+1 = WEEK(s_birth)

-- 49、查询本月过生日的学生

	select * from student where MONTH(DATE_FORMAT(NOW(),'%Y%m%d')) = MONTH(s_birth)
	
-- 50、查询下月过生日的学生
	select * from student where MONTH(DATE_FORMAT(NOW(),'%Y%m%d'))+1 = MONTH(s_birth)