как получить первые 9 и другие данные на основе отсортированного по количеству (entity_id) наибольшего числа лучших 9, а затем объединить остальные данные в категорию «другие»

Question

Следующий запрос выполняет все:

SELECT count(entity_id), cim.institute_id, cfi.name_ FROM ci_certification_students cis INNER JOIN ci_certification_master cim ON cis.certificate_id = cim.certificate_id
INNER JOIN ci_finalized_institute cfi ON cfi.institute_id=cim.institute_id
WHERE cis.status_id=4 AND cim.institute_id is not null group by cim.institute_id order by count(entity_id) desc limit 100;

Я попробовал следующее:

SELECT seqnum,institute_id, (CASE WHEN seqnum > 9 THEN 'others' ELSE name_ END) as name_, sum(total_certi) FROM 
(select count(cis.entity_id) as total_certi, cim.institute_id, cfi.name_ as certiName, ROW_NUMBER() OVER (ORDER BY COUNT(cis.entity_id) desc) as seqnum
FROM certificationdb.ci_certification_students cis 
INNER JOIN ci_certification_master cim ON cis.certificate_id = cim.certificate_id
INNER JOIN certificationdb.ci_finalized_institute cfi ON cim.institute_id=cfi.institute_id
WHERE cis.status_id=4 AND cim.institute_id is not null group by cim.institute_id ORDER BY 
count(cis.entity_id)desc)c GROUP BY (CASE WHEN seqnum> 9 THEN 'others' ELSE name_ END)
ORDER BY seqnum;

Любая помощь будет оценена ...

Answer 1

Использование row_number() и два уровня агрегации:

SELECT (CASE WHEN seqnum < 10 THEN institute_id END) as institute_id,
       (CASE WHEN seqnum < 10 THEN name_ ELSE 'OTHERS' END) as name,
       SUM(cnt) as cnt
FROM (SELECT cim.institute_id, cfi.name_, COUNT(*) as cnt,
             ROW_NUMBER() OVER (ORDER BY COUNT(*) DESC) as seqnum
      FROM ci_certification_students cis INNER JOIN 
           ci_certification_master cim
           ON cis.certificate_id = cim.certificate_id INNER JOIN
           ci_finalized_institute cfi ON 
           cfi.institute_id = cim.institute_id
      WHERE cis.status_id = 4 AND cim.institute_id is not null
      GROUP BY cim.institute_id, cfi.name_
     ) c
GROUP BY institute_id, name
ORDER BY MIN(seqnum);