實現效果，求各年齡段使用者數及佔比

1)oracle版本

 1 with temp as
 2  (select t.birth_type, sum(t.user_cnt) as user_cnt
 3     from dw_yq.bst_rpt_yq_pag_ratio_m t
 4    where t.nc_date >= '20200726' --時間過濾
 5      and t.nc_date <= '20200726'
 6    group by t.birth_type)
 7 select t2.type_name,
 8        nvl(t1.user_cnt, 0
 
) as user_cnt,
 9        round(ratio_to_report(nvl(t1.user_cnt, 0)) over() * 100, 4) as tkt_cnt_ratio
10   from temp t1, dim_user_birth_type t2
11  where t2.type_name = t1.birth_type(+)
12  order by t2.sort_flag

2）mysql版本

 1 SELECT
 2     t1.type_name AS cntname,
 3     ifnull(t2.user_cnt, 0) AS cnt,
 4
 
 
 5 IF (
 6     ifnull(t3.all_user_cnt, 0) = 0,
 7     0,
 8     ifnull(t2.user_cnt, 0) / ifnull(t3.all_user_cnt, 0) * 100
 9 ) AS ratio
10 FROM
11     dw_center.dim_user_birth_type t1
12 LEFT JOIN (
13     SELECT
14         t.birth_type,
15         sum(t.user_cnt) AS user_cnt
16     FROM
17         dw_yq.bst_rpt_yq_pag_ratio_d t
 
18     WHERE
19         t.nc_date >= '20200726'
20     AND t.nc_date <= '20200726'
21     GROUP BY
22         t.birth_type
23 ) t2 ON t1.type_name = t2.birth_type
24 JOIN (
25     SELECT
26         sum(t.user_cnt) AS all_user_cnt
27     FROM
28         dw_yq.bst_rpt_yq_pag_ratio_d t
29     WHERE
30         t.nc_date >= '20200726'
31     AND t.nc_date <= '20200726'
32 ) t3
33 ORDER BY
34     t1.sort_flag

3）Impala版本

with t1 as
 (select tp.birth_type, tp.user_cnt, sum(tp.user_cnt) over() as all_user_cnt
    from (select t.birth_type, sum(t.user_cnt) as user_cnt
            from dw_yq.bst_rpt_yq_pag_ratio_d t
           where t.dt_date >= '20200726' --時間過濾
             and t.dt_date <= '20200726'
           group by t.birth_type) tp)
select t2.type_name AS cntname,
       ifnull(t1.user_cnt, 0) AS cnt,
       IF(ifnull(t1.all_user_cnt, 0) = 0,
          0,
          round(ifnull(t1.user_cnt, 0) / ifnull(t1.all_user_cnt, 0) * 100,
          4)) AS ratio
  from dw_dim_center.dim_user_birth_type t2
  left join t1
    on t2.type_name = t1.birth_type

上面dim_user_birth_type表用於補充維度

根據上面程式碼看來，oracle版本的比較簡短，支援with子句，ratio_to_report() over() 函式很方便的就求出佔比；Impala也支援with子句，是的程式碼結構更加清晰，但是需要自己計算佔比；mysql使用效果最差。

簡單記錄下.....