大厂的SQL面试题都是怎样的（附赠答案）

create table if not exists test.nil_goods_category asselect goods_id,case when nn<= 10 then 'top10'      when nn<= 20 then 'top10~top20'      else 'other' end as goods_groupfrom(    select goods_id    ,row_number() over(partition by goods_id order by sale_sum desc) as nn    from    (        select goods_id,sum(amount) as sale_sum        from order        group by 1    ) aa) bb;select b.goods_group,count(distinct a.uid) as numfrom pv a left join test.nil_goods_category b on a.goods_id = b.goods_idgroup by 1;

1.select count(distinct g_id) as event_goods_numfrom goods_eventwhere (t1<=t4 and t1>=t3) or (t2>=t3 and t2<=t4)

2.select count(distinct g_id) as event_goods_numfrom goods_eventwhere (t1<=t4 and t1>=t3) union all

select a.goods_id,a.timefrom event a inner join(    select goods_id,count(*)    from event    group by gooods_id    order by count(*) desc    limit 1) bon a.goods_id = b.goods_idorder by a.goods_id,a.time desc

drop table if exists koo.nil_temp0222_a2;create table if not exists koo.nil_temp0222_a2 asselect *    ,row_number() over(partition by userid order by inserttime) as nn1from(    select a.*    ,b.inserttime as inserttime_aftr    ,datediff(b.inserttime,a.inserttime) as session_diff  from  (    select userid,inserttime      ,row_number() over(partition by userid order by inserttime asc) nn    from koo.nil_temp0222     where userid = 1900000169  ) a     left join  (     select userid,inserttime      ,row_number() over(partition by userid order by inserttime asc) nn    from koo.nil_temp0222     where userid = 1900000169  ) b  on a.userid =  b.userid and a.nn = b.nn-1) aawhere session_diff >10 or nn = 1order by userid,inserttime;

drop table if exists koo.nil_temp0222_a2_1;create table if not exists koo.nil_temp0222_a2_1 asselect a.*,case when b.nn is null then a.nn+3 else b.nn end as nn_endfrom koo.nil_temp0222_a2 a left join koo.nil_temp0222_a2 b on a.userid = b.userid and a.nn1 = b.nn1 - 1;

select a.*,b.nn1 as session_idfrom(  select userid,inserttime    ,row_number() over(partition by userid order by inserttime asc) nn  from koo.nil_temp0222   where userid = 1900000169) aleft join koo.nil_temp0222_a2_1 b on a.userid = b.useridand a.nn>=b.nnand a.nn

select *from(  select *  ,rank() over(partition by mm order by dd desc) as nn1  ,row_number() over(partition by mm,dd order by inserttime desc) as nn2  from  (select cast(right(to_date(inserttime),2) as int) as dd,month(inserttime) as mm,userid,inserttime  from koo.nil_temp0222) aa ) bb where nn1 = 1 and nn2<=3;

select a.*,b.num as num2,c.num as num3from table  a left join table bon a.userid = b.useridand a.dt = date_add(b.dt,-1)left join table con a.userid = c.useridand a.dt = date_add(c.dt,-2)where b.num>100and a.num>100and c.num>100

1.select aa.*from(  select *,concat(d1,d2,d3……d20) as mmd  from table) aa left join(  select id,concat(d1,d2,d3……d20) as mmd  from table) bb on aa.id = bb.idand aa.mmd = bb.mmd

2.select a.*,sum(d1_jp,d2_jp……,d20_jp) as same_judgefrom(  select a.*  ,case when a.d1 = b.d1 then 1 else 0 end as d1_jp  ,case when a.d2 = b.d2 then 1 else 0 end as d2_jp  ,case when a.d3 = b.d3 then 1 else 0 end as d3_jp  ,case when a.d4 = b.d4 then 1 else 0 end as d4_jp  ,case when a.d5 = b.d5 then 1 else 0 end as d5_jp  ,case when a.d6 = b.d6 then 1 else 0 end as d6_jp  ,case when a.d7 = b.d7 then 1 else 0 end as d7_jp  ,case when a.d8 = b.d8 then 1 else 0 end as d8_jp  ,case when a.d9 = b.d9 then 1 else 0 end as d9_jp  ,case when a.d10 = b.d10 then 1 else 0 end as d10_jp  ,case when a.d20 = b.d20 then 1 else 0 end as d20_jp  ,case when a.d11 = b.d11 then 1 else 0 end as d11_jp  ,case when a.d12 = b.d12 then 1 else 0 end as d12_jp  ,case when a.d13 = b.d13 then 1 else 0 end as d13_jp  ,case when a.d14 = b.d14 then 1 else 0 end as d14_jp  ,case when a.d15 = b.d15 then 1 else 0 end as d15_jp  ,case when a.d16 = b.d16 then 1 else 0 end as d16_jp  ,case when a.d17 = b.d17 then 1 else 0 end as d17_jp  ,case when a.d18 = b.d18 then 1 else 0 end as d18_jp  ,case when a.d19 = b.d19 then 1 else 0 end as d19_jp  from table a   left join table b   on a.id = b.id ) aawhere sum(d1_jp,d2_jp……,d20_jp) = 19

select aa.uid1,aa.uid2,sum(star_multi) as resultfrom(  select a.uid as uid1  ,b.uid as uid2  ,a.goods_id  ,a.star * b.star as star_multi  from t a   left join t b   on a.goods_id = b.goods_id  and a.udi<>b.uid  ) aa group by 1,2

select uid1,uid2,sum(multiply) as resultfrom(select t.uid as uid1, t.uid as uid2, goods_id,a.star*star as multiplyfrom a left join b on a.goods_id = goods_idand a.uid<>uid) aagroup by goods

select a.*,b.s_mid_n,c.l_mid_n,avg(b.s_mid_n,c.l_mid_n)from(  select  case when mod(count(*),2) = 0 then count(*)/2 else (count(*)+1)/2 end as s_mid  ,case when mod(count(*),2) = 0 then count(*)/2+1 else (count(*)+1)/2 end as l_mid    from table) a left join(  select id,num,row_number() over(partition by id order by num asc) nn  from table) b on a.s_mid = b.nnleft join(  select id,num,row_number() over(partition by id order by num asc) nn  from table) c  on a.l_mid = c.nn

select distinct credit_levelfrom(  select credit_level,count(distinct nn) as number  from  (    select userid,credit_level,inserttime,month(inserttime) as mm    ,weekofyear(inserttime) as week    ,dense_rank() over(partition by credit_level,month(inserttime) order by weekofyear(inserttime) asc) as nn    from koo.nil_temp0222     where substring(inserttime,1,7) = '2019-12'    order by credit_level ,inserttime    ) aa   group by 1  ) bbwhere number = (select count(distinct weekofyear(inserttime))from koo.nil_temp0222 where substring(inserttime,1,7) = '2019-12')