Hive生成日期维度表
1、时间维表（完整版）
1）、 建表
-- 时间维表 完整版
create table if not exists dim.dim_date (
date_id string comment '日期(yyyymmdd)'
,datestr string comment '日期(yyyy-mm-dd)'
,date_name string comment '日期名称中文'
,weekid int comment '周(0-6,周日~周六)'
,week_cn_name string comment '周_名称_中文'
,week_en_name string comment '周_名称_英文'
,week_en_nm string comment '周_名称_英文缩写'
,yearmonthid string comment '月份id(yyyymm)'
,yearmonthstr string comment '月份(yyyy-mm)'
,monthid int comment '月份id（1-12）'
,monthstr string comment '月份'
,month_cn_name string comment '月份名称_中文'
,month_en_name string comment '月份名称_英文'
,month_en_nm string comment '月份名称_简写_英文'
,quarterid int comment '季度id（1-4）'
,quarterstr string comment '季度名称'
,quarter_cn_name string comment '季度名称_中文'
,quarter_en_name string comment '季度名称_英文'
,quarter_cn_nm string comment '季度名称_简写中文'
,quarter_en_nm string comment '季度名称_简写英文'
,yearid int comment '年份id'
,year_cn_name string comment '年份名称_中文'
,year_en_name string comment '年份名称_英文'
,month_start_date string comment '当月1号(yyyy-mm-dd)'
,month_end_date string comment '当月最后日期(yyyy-mm-dd)'
,month_timespan int comment '月跨天数'
,week_of_year int comment '当年第几周'
,workday_flag string comment '是否工作日(周一至周五Y，否则:N)'
,weekend_flag string comment '是否周末(周六和周日Y,否则:N)'
)comment '日期维度表'
stored as orc;
2）、插入数据
insert overwrite table dim.dim_date
select date_id
,datestr
,concat(yearid,'年',monthid,'月',substr(datestr,9,2),'日') as date_name
,weekid
,case weekid when 0 then '星期日'
when 1 then '星期一'
when 2 then '星期二'
when 3 then '星期三'
when 4 then '星期四'
when 5 then '星期五'
when 6 then '星期六'
end as week_cn_name
,case weekid when 0 then 'Sunday'
when 1 then 'Monday'
when 2 then 'Tuesday'
when 3 then 'Wednesday'
when 4 then 'Thurday'
when 5 then 'Friday'
when 6 then 'Saturday'
end as week_en_name
,case weekid when 0 then 'Sun'
when 1 then 'Mon'
when 2 then 'Tues'
when 3 then 'Wed'
when 4 then 'Thur'
when 5 then 'Fri'
when 6 then 'Sat'
end as week_en_nm
,substr(date_id,1,6) as yearmonthid
,substr(datestr,1,7) as yearmonthstr
,monthid
,concat(yearid,'年',monthid,'月') as monthstr
,concat(monthid,'月') as month_cn_name
,case monthid when 1 then 'January'
when 2 then 'February'
when 3 then 'March'
when 4 then 'April'
when 5 then 'May'
when 6 then 'June'
when 7 then 'July'
when 8 then 'August'
when 9 then 'September'
when 10 then 'October'
when 11 then 'November'
when 12 then 'December'
end as month_en_name
,case monthid when 1 then 'Jan'
when 2 then 'Feb'
when 3 then 'Mar'
when 4 then 'Apr'
when 5 then 'May'
when 6 then 'Jun'
when 7 then 'Jul'
when 8 then 'Aug'
when 9 then 'Sept'
when 10 then 'Oct'
when 11 then 'Nov'
when 12 then 'Dec'
end as month_en_nm
,quarterid
,concat(yearid,quarterid) as quarterstr
,concat(yearid,'年第',quarterid,'季度') as quarter_cn_name
,concat(yearid,'Q',quarterid) as quarter_en_name
,case quarterid when 1 then '第一季度'
when 2 then '第二季度'
when 3 then '第三季度'
when 4 then '第四季度'
end as quarter_cn_nm
,concat('Q',quarterid) as quarter_en_nm
,yearid
,concat(yearid,'年') as year_cn_name
,yearid as year_en_name
,month_start_date
,month_end_date
,datediff(month_end_date,month_start_date) + 1 as month_timespan
,week_of_year
,case when weekid in (1,2,3,4,5) then 'Y' else 'N' end as workday_flag
,case when weekid in (0,6) then 'Y' else 'N' end as weekend_flag
from
(
select from_unixtime(unix_timestamp(datestr,'yyyy-MM-dd'),'yyyyMMdd') as date_id
,datestr as datestr
,pmod(datediff(datestr, '2012-01-01'), 7) as weekid
,concat(substr(datestr,1,4),substr(datestr,6,2)) as yearmonthid
,substr(datestr,1,7) as yearmonthstr
,cast(substr(datestr,6,2) as int) as monthid
,case when cast(substr(datestr,6,2) as int) <= 3 then 1
when cast(substr(datestr,6,2) as int) <= 6 then 2
when cast(substr(datestr,6,2) as int) <= 9 then 3
when cast(substr(datestr,6,2) as int) <= 12 then 4
end as quarterid
,substr(datestr,1,4) as yearid
,date_sub(datestr,dayofmonth(datestr)-1) as month_start_date --当月第一天
,last_day(date_sub(datestr,dayofmonth(datestr)-1)) month_end_date --当月最后一天
,weekofyear(datestr) as week_of_year
from
(
select date_add('2000-01-01',t0.pos) as datestr
from
(
select posexplode(
split(
repeat('o', datediff(from_unixtime(unix_timestamp('20991231','yyyymmdd'),'yyyy-mm-dd'), '2000-01-01')), 'o'
)
)
) t0
) t
) A
;
2、解释一下
使用 posexplode() 函数，获得 [2000-01-01, 2099-12-31] 的日期列表：
select date_add('2000-01-01',t0.pos) as datestr
from (
select posexplode(
split(
repeat('o', datediff(from_unixtime(unix_timestamp('20991231','yyyymmdd'),'yyyy-mm-dd'), '2000-01-01')), 'o'
)
)
) t0
- posexplode(ARRAY a)，与 explode 类似，行转列函数，返回的
pos列用来记录序号，序号从 0 开始，即t0.pos取[0,datediff]。
官方解释：将数组分解为多行，并带有 int 类型的附加位置列（原始数组中项的位置，从 0 开始）。返回包含两列 （pos，val） 的行集，数组中的每个元素各占一行。 - repeat用来构建split分割所需的字符串（以’o’分割的字符串），datediff取日差。
3、熄灯
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