Available in versions: Dev (3.20) | Latest (3.19) | 3.18

JSON_KEYS

Applies to ✅ Open Source Edition   ✅ Express Edition   ✅ Professional Edition   ✅ Enterprise Edition

The JSON_KEYS function is a non-standard JSON function inspired by MySQL's JSON_KEYS function, which can be used to extract keys of a JSON object into an JSON array.

SELECT json_keys(json_object(
  KEY 'a' VALUE 1
  KEY 'b' VALUE 2
))
create.select(jsonKeys(jsonObject(
          key("a").value(1),
          key("b").value(2))))
      .fetch();

The result would look like this:

+-----------+
| json_keys |
+-----------+
| ["a","b"] |
+-----------+

Dialect support

This example using jOOQ:

jsonKeys(jsonObject(key("a").value(1), key("b").value(2)))

Translates to the following dialect specific expressions:

Aurora Postgres, Postgres, YugabyteDB

(
  SELECT coalesce(
    json_agg(j),
    json_build_array()
  )
  FROM json_object_keys(json_build_object(
    'a', CAST(1 AS int),
    'b', CAST(2 AS int)
  )) as j(j)
)

CockroachDB

(
  SELECT coalesce(
    json_agg(j),
    json_build_array()
  )
  FROM json_object_keys(json_build_object(
    'a', CAST(1 AS int4),
    'b', CAST(2 AS int4)
  )) as j(j)
)

MariaDB

json_keys(json_merge_preserve(
  '{}',
  json_object('a', 1),
  json_object('b', 2)
))

MySQL

json_keys(json_object(
  'a', 1,
  'b', 2
))

Oracle

json_keys(json_object(
  KEY 'a' VALUE 1,
  KEY 'b' VALUE 2
))

Snowflake

object_keys(object_construct_keep_null(
  'a', 1,
  'b', 2
))

SQLite

(
  SELECT json_group_array("key")
  FROM json_each(json_object(
    'a', 1,
    'b', 2
  ))
)

Trino

CAST(map_keys(cast(CAST(map_from_entries(ARRAY[
  row(
    'a',
    CAST(1 AS json)
  ),
  row(
    'b',
    CAST(2 AS json)
  )
]) AS json) as map(varchar, json))) AS json)

ASE, Access, Aurora MySQL, BigQuery, DB2, Derby, DuckDB, Exasol, Firebird, H2, HSQLDB, Hana, Informix, MemSQL, Redshift, SQLDataWarehouse, SQLServer, Sybase, Teradata, Vertica

/* UNSUPPORTED */

(These are currently generated with jOOQ 3.20, see #10141), or translate your own on our website

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