Question

Q1和Q2在不同方面是相同的问题。如果数据存储为元组（键，值），那么任何SQL都能得到相同的结果？

(1,3)(2,5)(4,7)
(1,3)(2,5)(3,4)
(2,3)(7,5)(10,4)

Q1：sumMap可以将Array更改为Tuple，但是如何将Tuple更改为Array？

select sumMap(a, b) from (
select array(1,2,4) as a, array(3,5,7) as b
union all
select array(1,2,3) as a, array(3,5,4) as b
union all
select array(2,7,10) as a, array(3,5,4) as b);

│ ([1,2,3,4,7,10],[6,13,4,7,5,4]) │

错误SQL：

select sumMap(a, b).[0], sumMap(a, b).[1] from tbl

[1,2,3,4,7,10]   [6,13,4,7,5,4]

第二季度：如何像sumMap这样按键求和数组？

select array(1,2,4) as a, array(3,5,7) as b
union all
select array(1,2,3) as a, array(3,5,4) as b
union all
select array(2,7,10) as a, array(3,5,4) as b

│ [1,2,4] │ [3,5,7] │
│ [2,7,10]│ [3,5,4] │
│ [1,2,3] │ [3,5,4] │

错误SQL：

select sumBykey(a, a), sumBykey(b, a).key2 from tbl

[1,2,3,4,7,10]   [6,13,4,7,5,4]

Answer 1

请参见tuple access operators。

SELECT
    sumMap(a, b) AS summap,
    summap.1 AS a1,
    summap.2 AS a2
FROM
(
    SELECT
        [1, 2, 4] AS a,
        [3, 5, 7] AS b
    UNION ALL
    SELECT
        [1, 2, 3] AS a,
        [3, 5, 4] AS b
    UNION ALL
    SELECT
        [2, 7, 10] AS a,
        [3, 5, 4] AS b
)

┌─summap──────────────────────────┬─a1─────────────┬─a2─────────────┐
│ ([1,2,3,4,7,10],[6,13,4,7,5,4]) │ [1,2,3,4,7,10] │ [6,13,4,7,5,4] │
└─────────────────────────────────┴────────────────┴────────────────┘

有什么功能（将元组更改为数组）或（按键求和数组）？

1 个答案: