一套sql面试题的mysql解法

select * from T order by c [desc] limit 20,10

update T
inner join (select a1,c1,d1 from T1) temp on t.a = temp.a1 
set t.c = temp.c1,t.d = temp.d1

select
temp.Year as Year,
group_concat(case when temp.Month = '01' then temp.am end) as 'M01',
group_concat(case when temp.Month = '02' then temp.am end) as 'M02',
group_concat(case when temp.Month = '03' then temp.am end) as 'M03',
group_concat(case when temp.Month = '04' then temp.am end) as 'M04'
from ODM_JYBB temp
group by Year

select now() as '日期(date)',
date_format(now(),'%Y-%m-%d %T') as '日期(string)',
CASE dayofweek(now()) 
when '1' then '日'
when '2' then '一'
when '3' then '二'
when '4' then '三'
when '5' then '四'
when '6' then '五'
when '7' then '六'
else '' end
 as '星期',
date_format(now(),'%Y-%m') as '月份',
EXTRACT(week from now()) as '第几周',
if(dayofweek(ADDDATE(now(),0))%7=1 or dayofweek(ADDDATE(now(),0))%7=0,"否","是") as 是否工作日

select
    t1.name as name01,
    t2.name as name02 
from
    team t1
    inner join team t2 on t1.name < t2.name 
order by
    t1.`name`