typeof

Reports the type of an any value or the distinct element types in an array.

Syntax

typeof(<expr>)

Arguments

Returns

For any, returns string naming the contained type. A NULL any value returns 'null'.

For array, returns an array of distinct element type names, including 'null' for NULL elements. Each type appears once. An empty array returns []; a NULL array returns NULL.

Examples

Investigate inconsistent amount types

A producer may switch an amount from a number to text. Inspect the contained type before deciding how to cast it.

VALUES
    ('evt-17', {'amount': 49.0}), ('evt-42', {'amount': '79.00'}),
    ('evt-63', {'channel': 'web'})
SELECT $0 AS event_id, $1 AS payload
SELECT event_id, typeof(payload['amount']) AS amount_type

+----------+-------------+
| event_id | amount_type |
+----------+-------------+
| evt-17   | float       |
| evt-42   | string      |
| evt-63   | null        |
+----------+-------------+

The missing amount field produces the type name 'null'.

Check the element types of an array

Inspect an item-ID array that unexpectedly contains a numeric ID.

SELECT typeof(['sku-1', 'sku-2', 42]) AS element_types

+------------------+
| element_types    |
+------------------+
| ["int","string"] |
+------------------+

For an array input, typeof returns the distinct element types rather than the string array. Their order may vary.