PG在阵列中删除公共部分

假设一个PostgreSQL查询2列的int各自为阵列[] [2]PG在阵列中删除公共部分

  track0       track1 
{{1,2},{5847,5848},{5845,5846}......} {{1,2},{5847,5848},{10716,10715}........} 

{{13,14},{1,2},{5847,5848},{284,285}........} {{13,14},{1,2},{5847,5848},{1284,1285}................}

我们怎样才能去除通用于列前导阵列除了最后的输出行一？在第一行{1,2}应该从两列中删除。在第二行{13,14},{1,2}应该从两栏中删除。

可以用sql来完成还是需要使用plpgsql？

我可以管理plpgsql，但想要sql解决方案。

来源

2017-10-19 tiblemont

给出相等对序列没有缺口的样品，

t=# with d(t0,t1) as (values 
     ('{{1,2},{5847,5848},{5845,5846}}'::int[][2],'{{1,2},{5847,5848},{10716,10715}}'::int[][2]) 
    , ('{{13,14},{1,2},{5847,5848},{284,285}}'::int[][2],'{{13,14},{1,2},{5847,5848},{1284,1285}}'::int[][2]) 
    ) 
    , u as (
     select * 
     from d 
     join unnest(t0) with ordinality t(e0,o0) on true 
     left outer join unnest(t1) with ordinality t1(e1,o1) on o0=o1 
    ) 
    , p as (
    select * 
    , case when (
     not lead(e0=e1) over w 
     or not lead(e0=e1,2) over w 
     or e0!=e1 
    ) AND (o1%2) = 1 
     then ARRAY[e0,lead(e0) over w] end r0 
    , case when (
     not lead(e0=e1) over w 
     or not lead(e0=e1,2) over w 
     or e0!=e1 
    ) AND (o1%2) = 1 
     then ARRAY[e1,lead(e1) over w] end r1 
    from u 
    window w as (partition by t0,t1 order by o0) 
    ) 
    select t0,t1,array_agg(r0),array_agg(r1) 
    from p 
    where r0 is not null or r1 is not null 
    group by t0,t1 
    ; 
        t0     |     t1     |   array_agg   |   array_agg 
---------------------------------------+-----------------------------------------+---------------------------+----------------------------- 
{{13,14},{1,2},{5847,5848},{284,285}} | {{13,14},{1,2},{5847,5848},{1284,1285}} | {{5847,5848},{284,285}} | {{5847,5848},{1284,1285}} 
{{1,2},{5847,5848},{5845,5846}}  | {{1,2},{5847,5848},{10716,10715}}  | {{5847,5848},{5845,5846}} | {{5847,5848},{10716,10715}} 
(2 rows)

你可以跳过复杂的一部分，如果你添加一些伎俩多维数组，看here和here

来源

2017-10-20 08:44:47

PG在阵列中删除公共部分

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