HiveSql整理 , 習題

unix_timestamp:返回當前或指定時間的時間戳

from_unixtime：將時間戳轉為日期格式

current_date：當前日期

current_timestamp：當前的日期加時間

to_date：抽取日期部分

year：獲取年

month：獲取月

day：獲取日

hour：獲取時

minute：獲取分

second：獲取秒

weekofyear：當前時間是一年中的第幾周

dayofmonth：當前時間是乙個月中的第幾天

months_between：兩個日期間的月份

add_months：日期加減月

datediff：兩個日期相差的天數

date_add：日期加天數

date_sub：日期減天數

last_day：日期的當月的最後一天

date_format : 按指定格式返回日期

round：四捨五入

ceil：向上取整

floor：向下

upper：轉大寫 l

ower：轉小寫

length：長度

trim：前後去空格

lpad：向左補齊，到指定長度

rpad：向右補齊，到指定長度

regexp_replace： select regexp_replace(『100-200』, 『(\d+)』, 『num』); 使用正規表示式匹配目標字串，匹配成功後替換！

size：集合中元素的個數

map_keys：返回map中的key

map_values: 返回map中的value

array_contains: 判斷array中是否包含某個元素

sort_array：將array中的元素排序

select videoid, uploader, views from gulivideo_orc order by views desc limit

10

select category_name, count(* ) c_n from gulivideo_orc lateral view explode(category) tmp as category_name --這個備表階段, 新加了字段 group by category_name order by c_n desc limit

10

select
category_name,
count(*
) c_n
from
(select
videoid,
uploader,
views,
category
from gulivideo_orc
order
by views desc
limit
20)t1
lateral view explode(t1.category) tmp as category_name
group
by category_name

select
category_name,
count(*
) c_n
from
(select
t3.videoid,
t3.category
from
(select
relatedid_name
from
(select
videoid,
uploader,
views,
relatedid
from gulivideo_orc
order
by views desc
limit
50)t1
lateral view explode(t1.relatedid) tmp as relatedid_name
) t2 join gulivideo_orc t3
on t2.relatedid_name=t3.videoid 
)t4 
lateral view explode(t4.category) tmp as category_name
group
by category_name
order
by c_n desc

select t1.videoid, t1.views, t1.category_name from (select videoid, views, category_name from gulivideo_orc lateral view explode(category) tmp as category_name )t1where t1.category_name= 'music' order by t1.views desc limit

10

select t2.videoid, t2.views, t2.category_name, t2.rk from (select t1.videoid, t1.views, t1.category_name, rank( )over (partition by t1.category_name order by t1.views desc ) rk --視窗函式不改變行數, 但是變列數, 並讓結果有序 from (select videoid, views, category_name from gulivideo_orc lateral view explode(category) tmp as category_name --若按類別分組 , 每個類別的每條資料拿不到 , 無法得到類別中的前10 --此時想到視窗函式不會改變表中資料的行數 )t1)t2 where t2.rk<=

10

select t2.uploader, t2.views from (select uploader, videos from gulivideo_user_orc order by videos desc limit 10)t1 join gulivideo_orc t2 on t1.uploader=t2.uploader order by t2.views desc limit

20

select
t3.uploader,
t3.views,
t3.rk
from
(select
t2.uploader,
t2.views,
rank(
)over
(partition
by t2.uploader order
by t2.views desc
) rk
from
(select
uploader,
videos
from gulivideo_user_orc
order
by videos desc
limit
10)t1 join gulivideo_orc t2
on t1.uploader=t2.uploader
)t3where t3.rk<=
20

select t2.uploader, t1.views from (select videoid, uploader, views from gulivideo_orc order by views desc limit 20) t1 join (select uploader, videos from gulivideo_user_orc order by videos desc limit 10) t2

on t1.uploader=t2.uploader

HiveSql整理 , 習題

hive sql優化整理

遞迴習題整理

LeetCode習題整理（一）

HiveSql整理 , 習題

hive sql優化整理

遞迴習題整理

LeetCode習題整理（一）

相關推薦