New versions: Dev (3.14)

JSON_ARRAYAGG

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

A data set can be aggregated into a org.jooq.JSON or org.jooq.JSONB array using JSON_ARRAYAGG

SELECT json_arrayagg(author.id)
FROM author
 
create.select(jsonArrayAgg(AUTHOR.ID))
      .from(AUTHOR)
      .fetch();

The result would look like this:

+---------------+
| json_arrayagg |
+---------------+
| [1,2]         |
+---------------+

Ordering aggregation contents

When aggregating data into an array or JSON array, ordering may be relevant. For this, use the ORDER BY clause in JSON_ARRAYAGG

SELECT json_arrayagg(author.id ORDER BY author.id DESC)
FROM author
 
create.select(jsonArrayAgg(AUTHOR.ID).orderBy(AUTHOR.ID.desc())
      .from(AUTHOR)
      .fetch();

The result would look like this:

+---------------+
| json_arrayagg |
+---------------+
| [2,1]         |
+---------------+

NULL handling

Some dialects support the SQL standard NULL ON NULL and ABSENT ON NULL syntax, which allows for including / excluding NULL values from aggregation. By default, SQL aggregate functions always exclude NULL values, but in the context of JSON data types, NULL may have a different significance:

SELECT 
  json_arrayagg(nullif(author.id, 1) NULL   ON NULL) AS c1,
  json_arrayagg(nullif(author.id, 1) ABSENT ON NULL) AS c2
FROM author
 
create.select(
        jsonArrayAgg(nullif(AUTHOR.ID, 1)).nullOnNull()  .as("c1"),
        jsonArrayAgg(nullif(AUTHOR.ID, 1)).absentOnNull().as("c2"))
      .from(AUTHOR)
      .fetch();

The result would look like this:

+----------+-----+
| C1       | C2  |
+----------+-----+
| [null,2] | [2] |
+----------+-----+

The effect is similar to that of the FILTER clause.

Dialect support

This example using jOOQ:

jsonArrayAgg(AUTHOR.ID)

Translates to the following dialect specific expressions:

-- AURORA_POSTGRES, COCKROACHDB, POSTGRES
json_agg(AUTHOR.ID)

-- DB2
CAST(('[' || listagg(AUTHOR.ID, ',') || ']') AS varchar(32672))

-- H2, ORACLE
json_arrayagg(AUTHOR.ID)

-- MARIADB, MYSQL
json_merge('[]', concat('[', group_concat(AUTHOR.ID SEPARATOR ','), ']'))

-- ACCESS, ASE, AURORA_MYSQL, CUBRID, DERBY, FIREBIRD, HANA, HSQLDB, INFORMIX, INGRES, MEMSQL, REDSHIFT, SQLDATAWAREHOUSE, 
-- SQLITE, SQLSERVER, SYBASE, TERADATA, VERTICA
/* UNSUPPORTED */

(These are currently generated with jOOQ 3.14, see #10141)

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