jsonb_agg function
The jsonb_agg(expression)
function aggregates all values indicated by its expression,
returning the values (including nulls) as a jsonb
array.
The input values to the aggregate can be filtered.
Syntax
Signatures
Parameter | Type | Description |
---|---|---|
expression | jsonb | The values you want aggregated. |
Return value
jsonb_agg
returns the aggregated values as a jsonb
array.
This function always executes on the data from value
as if it were sorted in ascending order before the function call. Any specified ordering is
ignored. If you need to perform aggregation in a specific order, you must specify ORDER BY
within the aggregate function call itself. Otherwise incoming rows are not guaranteed any order.
Details
Usage in dataflows
While jsonb_agg
is available in Materialize, materializing jsonb_agg(expression)
is considered an incremental view maintenance anti-pattern. Any change to the data
underlying the function call will require the function to be recomputed entirely,
discarding the benefits of maintaining incremental updates.
Instead, we recommend that you materialize all components required for the
jsonb_agg
function call and create a non-materialized view using jsonb_agg
on top of that. That pattern is illustrated in the following statements:
CREATE MATERIALIZED VIEW foo_view AS SELECT * FROM foo;
CREATE VIEW bar AS SELECT jsonb_agg(foo_view.bar) FROM foo_view;
Examples
SELECT jsonb_agg(1);
jsonb_agg
-----------
[1]
SELECT jsonb_agg('example'::text);
jsonb_agg
-------------
["example"]