对 JSON_OBJECT 和 DISTINCT 的 SQL 查询

Question

I'm trying to output a query result as a JSON object using JSON_ARRAYAGG(JSON_OBJECT()) (that works just fine). I can't use DISTINCT within the JSON_OBJECT command and using GROUP BY will not output the whole result as one JSON but as many rows (each then a JSON). Example:

SELECT JSON_ARRAYAGG(JSON_OBJECT(\'id\', `id`, ...)) FROM table

That works fine but doesn't filter out the duplicates. I tried :

SELECT JSON_ARRAYAGG(JSON_OBJECT(\'id\', `id`, \'title\', DISTINCT(`title`), ...)) FROM table

And :

SELECT JSON_ARRAYAGG(JSON_OBJECT(\'id\', `id`, \'title\', `title`, ...)) FROM table GROUP BY `title`

But the former is wrong (syntax wise) and the latter splits the result in multiple rows. Can someone explain me how to achieve this? Like :

SELECT JSON_ARRAYAGG(JSON_OBJECT(\'id\', `id`, ...)) FROM table

But with unique results only.

Answer 1

Can you wrap the duplicated query as a subquery and distinct from it?

select distinct xyz from ( SELECT JSON_ARRAYAGG(JSON_OBJECT(\\'id\\', id , ...)) as xyz FROM table) table1 );