`JSON_ARRAYAGG`

Applies to: ✅ Data 360 SQL ✅ Tableau Hyper API

Aggregates the input values from a group into a JSON array, using an optional, user-supplied order.

Syntax

1json_arrayagg([DISTINCT] <value> [ORDER BY <sort_expression> [ASC | DESC] [NULLS { FIRST | LAST }] [, ...]] [NULL ON NULL | ABSENT ON NULL])

DISTINCT: Keeps only distinct values. When you use DISTINCT, the ORDER BY expression (including its collation) must match <value>.
ORDER BY <sort_expression> [, ...]: Orders the elements within the array (an aggregate-local ordering). Each sort key accepts ASC / DESC and NULLS FIRST / NULLS LAST.
ABSENT ON NULL: Skips NULL inputs so they don’t appear in the array. This is the default.
NULL ON NULL: Keeps NULL inputs as JSON null elements.

A json value containing the aggregated array.

Null handling:

With the default ABSENT ON NULL, NULL inputs are dropped. A group whose values are all NULL returns an empty array ([]).
With NULL ON NULL, NULL inputs are kept as JSON null elements.

The FILTER clause isn’t supported for json_arrayagg.
If no ORDER BY is specified, the resulting array has an implementation-defined, non-deterministic order.
json_arrayagg with ORDER BY isn’t supported in combination with ROLLUP, CUBE, or GROUPING SETS.
The <value> is serialized to JSON using the json_scalar conversion rules.

Order elements by id and drop the NULL name (the default behavior).

1SELECT json_arrayagg(name ORDER BY id ABSENT ON NULL)
2FROM (VALUES (2, 'Grace'), (1, 'Ada'), (3, NULL)) AS people(id, name);

Returns ["Ada","Grace"].

Use NULL ON NULL to retain NULL inputs as JSON null elements.

1SELECT json_arrayagg(v ORDER BY k NULL ON NULL)
2FROM (VALUES (20, 1), (NULL, 2), (30, 3)) AS t(v, k);

Returns [20,null,30].

Build a JSON array of product names for each category.

1SELECT category,
2       json_arrayagg(product_name ORDER BY product_name)
3FROM products
4GROUP BY category;

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