在子查询中排序

Question

HOW TO GET SUBQUERY DATA ASEC ORDER IN ORACLE DB. BECAUSE IN SUBQUERY ORDER BY IS NOT WORKING

SELECT JSON_OBJECT(

'jobId' VALUE a.job_id,

'change_order' VALUE (SELECT JSON_ARRAYAGG( JSON_OBJECT(

'jobId' VALUE JOB_ID,

'changeNbr' VALUE CHANGE_NBR,

'changeDesc' VALUE CHANGE_DESC,

'status' VALUE CHANGE_STATUS

RETURNING CLOB)

RETURNING CLOB)

from builder_change_order_view

where job_id =${jobId}

AND rownum < 4

ORDER BY change_nbr )

),

This is the sample output, actually, I want an array in an object in ascending order {"change_number":1, "qwerty":[{"samp1": "test1"},{"samp2": "test2"},{"samp3": "test3"}]}. ie, array values in ascending order({"":"", array:[1,2,3,5]})

Answer 1

You should use the JSON_ARRAYAGG 's own ORDER BY clause:

JSON_ARRAYAGG(JSON_OBJECT(...) ORDER BY change_nbr)

Note that your ROWNUM filtering doesn't work correctly this way. It filters by arbitrary ROWNUM prior to ordering, so if you just want to aggregate the top 3 values, you'll have to use a derived table for this:

SELECT JSON_ARRAY_AGG(JSON_OBJECT(...) ORDER BY change_nbr)
FROM (
  SELECT *
  FROM builder_change_order_view
  WHERE job_id = ${jobId}
  ORDER BY change_nbr
  FETCH FIRST 3 ROWS ONLY
) t