由于PostgreSQL内置的聚合函数array_agg支持的数组聚合实际上是将多个数组聚合为多维数组。并不是一维数组。 例如：. postgres=# select array_agg(arr) ... ... <看更多>

Use an ORDER BY, like this example from the manual: SELECT array_agg(a ORDER BY b DESC) FROM table;. ... <看更多>

I am trying to write a PostgreSQL array_agg() variant that returns the empty array '{}' instead of NULL. Trying to avoid the performance hit ... ... <看更多>

merge array of arrays in postgresql with array_agg - array_of_arrays.sql. ... --select ARRAY(select distinct unnest(array_agg(category.arr))). ... <看更多>

... #24 — Array programming via unnest(), array_agg, WITH ORDINALITY ... Step by Step Javascript and ... ... <看更多>