PostgreSQL - 将integer []类型的聚合列转换为整数[]类型

Question

我的表有一个integer []类型的列。我希望按col1分组，求和col2，然后合并col3中的数组。

my_table
+-------------------------+
| col1 | col2 | col3      |
| ---- | ---- | --------- |
| qwer | 5    | {1,2,3,4} |
| asdf | 10   | {5,6,7,8} |
| qwer | 2    | {4,9,10}  |
+-------------------------+
SELECT col1, SUM(col2) AS sum, ???(col3) AS merge
FROM my_table
GROUP BY col1

This output would be acceptable:
=> 
+--------------------------------+
| col1 | sum | merge             | 
| ---- | --- | ----------------- |
| qwer | 7   | {1,2,3,4,4,9,10}  | 
| asdf | 10  | {5,6,7,8}         |
+--------------------------------+

The output would be ideal (the elements in the integer array are unique):
=> 
+------------------------------+
| col1 | sum | merge           | 
| ---- | --- | --------------- |
| qwer | 7   | {1,2,3,4,9,10}  | 
| asdf | 10  | {5,6,7,8}       |
+------------------------------+

对于???我已经尝试使用array_agg以及使用string_agg将数组转换为字符串，然后转换回数组。我无法让任何这些解决方案起作用。我错过了一个简单的解决方案或功能吗？

Answer 1

PostgreSQL array_agg函数不接受数组参数。 这是你的解决方案：

SQL命令：

SELECT
    xxx.col1,sum(xxx.col2),array_agg(xxx.one_col) 
FROM (select col1,col2,unnest(col3) as one_col from tmp2) AS xxx 
GROUP BY xxx.col1;