Puoi usare LEFT JOIN
invece di Sub-Query
.
Prova questo:
SELECT e.id, e.table_code,g.*
FROM events e
LEFT JOIN (SELECT MIN(date_time) date_time,
SUM(score) score,
type,
post_id,
table_code,
comment_id,
context
FROM events
WHERE author_id = 32
GROUP BY type, post_id, table_code, comment_id, context
ORDER BY MIN(date_time) DESC
LIMIT 15 ) g ON e.table_code = g.table_code AND e.date_time >= g.date_time
WHERE e.author_id = 32
ORDER BY seen ASC, e.date_time DESC