拉链表

1.数据准备

create table sospdm.tmp_ods_user
(
     cust_num   string comment '会员编码'
    ,mbl_phone  string comment '会员手机号'
)partitioned by (statis_date string comment '统计时间')
stored as rcfile 
;

set hive.exec.dynamic.partition=true;   
set hive.exec.dynamic.partition.mode=nonstrict;
insert overwrite table sospdm.tmp_ods_user partition (statis_date)
select '001' as cust_num,'111111' as mbl_phone,'20170101' as statis_date from sospdm.dual union all
select '002' as cust_num,'222222' as mbl_phone,'20170101' as statis_date from sospdm.dual union all
select '003' as cust_num,'333333' as mbl_phone,'20170101' as statis_date from sospdm.dual union all
select '004' as cust_num,'444444' as mbl_phone,'20170101' as statis_date from sospdm.dual union all

select '001' as cust_num,'111111' as mbl_phone,'20170102' as statis_date from sospdm.dual union all
select '002' as cust_num,'233333' as mbl_phone,'20170102' as statis_date from sospdm.dual union all
select '003' as cust_num,'333333' as mbl_phone,'20170102' as statis_date from sospdm.dual union all
select '004' as cust_num,'432432' as mbl_phone,'20170102' as statis_date from sospdm.dual union all
select '005' as cust_num,'555555' as mbl_phone,'20170102' as statis_date from sospdm.dual union all

select '001' as cust_num,'111111' as mbl_phone,'20170103' as statis_date from sospdm.dual union all
select '002' as cust_num,'233333' as mbl_phone,'20170103' as statis_date from sospdm.dual union all
select '003' as cust_num,'333333' as mbl_phone,'20170103' as statis_date from sospdm.dual union all
select '004' as cust_num,'654321' as mbl_phone,'20170103' as statis_date from sospdm.dual union all
select '005' as cust_num,'115115' as mbl_phone,'20170103' as statis_date from sospdm.dual union all
select '006' as cust_num,'666666' as mbl_phone,'20170103' as statis_date from sospdm.dual union all

select '001' as cust_num,'111111' as mbl_phone,'20170104' as statis_date from sospdm.dual union all
select '002' as cust_num,'233333' as mbl_phone,'20170104' as statis_date from sospdm.dual union all
select '003' as cust_num,'333333' as mbl_phone,'20170104' as statis_date from sospdm.dual union all
select '004' as cust_num,'654321' as mbl_phone,'20170104' as statis_date from sospdm.dual union all
select '005' as cust_num,'115115' as mbl_phone,'20170104' as statis_date from sospdm.dual union all
select '006' as cust_num,'666767' as mbl_phone,'20170104' as statis_date from sospdm.dual;

2.拉链逻辑

-- 全量拉链
-- 初始化拉链表
create table sospdm.tmp_dwd_his
(
     cust_num string comment '会员编码'
    ,mbl_phone string comment '手机号'
    ,start_date string comment '开始时间'
)partitioned by (end_date string comment '结束时间')
;

insert overwrite table sospdm.tmp_dwd_his partition(end_date)
select
     cust_num
    ,mbl_phone
    ,'20170101' as statis_date
    ,'99991231' as end_date
from tmp_ods_user where statis_date='20170101'
;

-- 取开链数据与今日全量数据对比 找出变化的

-- 字段改变或者不变的
insert overwrite table sospdm.tmp_dwd_his partition(end_date)
select 
     t1.cust_num
    ,t1.mbl_phone
    ,'${statis_date}' as start_date
    ,'99991231' as end_date
from
(
    select
         cust_num
        ,mbl_phone
    from tmp_ods_user where statis_date='${statis_date}'
) t1
left join 
(
    select
         cust_num
        ,mbl_phone
    from tmp_dwd_his where start_date<='${statis_date}' and end_date>='${statis_date}'
) t2 
on t1.cust_num=t2.cust_num
where t2.cust_num is null -- 新增
or t1.mbl_phone <> t2.mbl_phone -- 改变

union all 

select 
     t1.cust_num
    ,t1.mbl_phone
    ,start_date
    ,'${statis_date}' as end_date   -- 改变的进行闭链
from
(
    select
         cust_num
        ,mbl_phone
    from tmp_ods_user where statis_date='${statis_date}'
) t1 
inner join 
(
    select
         cust_num
        ,mbl_phone
        ,start_date
        ,end_date
    from tmp_dwd_his where start_date<='${statis_date}' and end_date>='${statis_date}'
) t2 
on t1.cust_num=t2.cust_num  
where t1.mbl_phone <> t2.mbl_phone-- 改变

union all 

select 
     t1.cust_num
    ,t1.mbl_phone
    ,start_date
    ,end_date
from
(
    select
         cust_num
        ,mbl_phone
    from tmp_ods_user where statis_date='${statis_date}'
) t1 
inner join 
(
    select
         cust_num
        ,mbl_phone
        ,start_date
        ,end_date
    from tmp_dwd_his where start_date<='${statis_date}' and end_date>='${statis_date}'
) t2 
on t1.cust_num=t2.cust_num and t1.mbl_phone = t2.mbl_phone -- 不变
;

3.拉链回滚

-- 回滚
-- 回滚日期之前的闭链 还是闭链

select 
     cust_num
    ,mbl_phone
    ,start_date
    ,end_date
from sospdm.tmp_dwd_his where end_date < '20170103'
--回滚日期之前的开链
union all 
select 
     cust_num
    ,mbl_phone
    ,start_date
    ,'99991231' as end_date
from sospdm.tmp_dwd_his where end_date >= '20170103'
;
原文地址:https://www.cnblogs.com/yin-fei/p/10840986.html