Postgresql 数组唯一聚合

Question

我有一张有结构的大桌子

CREATE TABLE t (
  id SERIAL primary key ,
  a_list int[] not null,
  b_list int[] not null,
  c_list int[] not null,
  d_list int[] not null,
  type int not null 
)

我想查询

a_list

、

b_list

、

c_list

、

d_list

中

type

的所有唯一值，如下所示

    select 
        some_array_unique_agg_function(a_list), 
        some_array_unique_agg_function(b_list), 
        some_array_unique_agg_function(c_list), 
        some_array_unique_agg_function(d_list),
        count(1) 
    where type = 30

例如对于这个数据

+----+---------+--------+--------+---------+------+
| id | a_list  | b_list | c_list | d_list  | type |
+----+---------+--------+--------+---------+------+  
| 1  | {1,3,4} | {2,4}  | {1,1}  | {2,4,5} | 30   |
| 1  | {1,2,4} | {2,4}  | {4,1}  | {2,4,5} | 30   |
| 1  | {1,3,5} | {2}    | {}     | {2,4,5} | 30   |
+----+---------+--------+--------+---------+------+

我想要下一个结果

+-------------+--------+--------+-----------+-------+
| a_list      | b_list | c_list | d_list    | count |
+-------------+--------+--------+-----------+-------+  
| {1,2,3,4,5} | {2,4}  | {1,4}  | {2,4,5}   | 3     |
+-------------+--------+--------+-----------+-------+

有

some_array_unique_agg_function

适合我的目的吗？

Answer 1

试试这个

with cte as (select 
        unnest( a_list::text[] )::integer as a_list, 
        unnest( b_list::text[] )::integer as b_list, 
        unnest( c_list::text[] )::integer as c_list, 
        unnest( d_list::text[] )::integer as d_list,
        (select count(type) from t) as type
    from t 
    where type = 30
)
select array_agg(distinct a_list),array_agg(distinct b_list)
,array_agg(distinct c_list),array_agg(distinct d_list),type from cte group by type ;

结果：

"{1,2,3,4,5}";"{2,4,NULL}";"{1,4,NULL}";"{2,4,5}";3

Answer 2

尝试对这篇文章中的旧答案进行此处理： 数组的所有排列

这列出了 INT 数组的唯一有序排列，该数组按某些内容（在我的例子中是row_id和instrument_id）分组，对于长度为<= 10 :

的数组来说，时间相当长

您可能需要安装 intarray 扩展...

WITH RECURSIVE data AS (
                           SELECT a1.instrument_id, ARRAY_AGG(a1.obs_pos ORDER BY a1.obs_pos) AS arr
                           FROM tmp_xxxx a1
                           GROUP BY 1
                       )
   , keys           AS (
                           SELECT instrument_id, GENERATE_SUBSCRIPTS(d.arr, 1) AS rn
                           FROM data d
                       )
   , cte            AS (
                           SELECT DISTINCT x.instrument_id
                                         , public.sort(x.initial_arr) AS initial_arr
                                         , public.sort(x.new_arr)     AS new_arr
                                         , public.sort(x.used_rn)     AS used_rn
                           FROM (
                                    SELECT d.instrument_id
                                         , d.arr               initial_arr
                                         , ARRAY [d.arr[k.rn]] new_arr
                                         , ARRAY [k.rn]        used_rn
                                    FROM data d
                                    JOIN keys k
                                         ON d.instrument_id = k.instrument_id
                                ) x
                           UNION ALL
                           SELECT DISTINCT c.instrument_id
                                         , public.sort(initial_arr)                      AS initial_arr
                                         , public.sort(c.new_arr || c.initial_arr[k.rn]) AS new_arr
                                         , public.sort(used_rn || k.rn)                  AS used_rn
                           FROM cte  c
                           JOIN keys k
                                ON c.instrument_id = k.instrument_id AND NOT (k.rn = ANY (c.used_rn))
                       )
INSERT
INTO tmp_xxxx( row_id
                      , instrument_id
                      , obs_pos_array
                      )
SELECT DISTINCT _row_id              AS row_id
              , cte.instrument_id
              , public.sort(new_arr) AS obs_pos_array
FROM cte
WHERE ARRAY_LENGTH(new_arr, 1) >= 2 -- change it to your needs
ON CONFLICT ON CONSTRAINT pk_xxxx DO NOTHING;