JSON_COMPOSEを使用して、テーブルから選択した値からJSONオブジェクトを作成します。
SELECT JSON_Compose(T.company, T.employees) FROM ( SELECT company, JSON_agg(empID AS id, empName AS name, empAge AS age) AS employees FROM emp_table GROUP BY company ) AS T;
結果:
JSON_Compose ------------ { "company" : "Teradata", "employees" : [ { "id" : 1, "name" : "Cameron", "age" : 24 }, { "id" : 2, "name" : "Justin", "age" : 34 } ] } { "company" : "Apple", "employees" : [ { "id" : 3, "name" : "Someone", "age" : 24 } ] }