pgsql 合并两个 json 数组

Question

我必须从表中选择两种类型的结果集并将它们合并到单个 json 数组中，例如

select col1,col2,col3 from table 1 order by col3 where col1< 2
union all 
select col1,col2,col3 from table 1 order by col1 where colo = 3

它说语法错误我相信由于 order by。

我需要在 json 数组中返回它，所以我正在尝试这样

SELECT (    SELECT json_agg(row)
            FROM (
         select col1,col2,col3 from table 1 order by col3 where col1< 2 ) row)
UNION ALL
  SELECT (SELECT json_agg(row)
            FROM (
        select col1,col2,col3 from table 1 order by col1 where colo = 3
) row)

它停用了两个 json 数组，即很明显，我如何在单个数组中制作它

谢谢，

Answer 1

在 UNION 之后做聚合：

select json_agg(t)
from (
  (select col1,col2,col3 from table1 order by col3 where col1< 2)
  union all 
  (select col1,col2,col3 from table1 order by col1 where colo = 3)
) t