也许这个？：
SELECT COUNT(t.longname) as cnt, l.location
FROM locations l
LEFT JOIN topics t
ON t.longname = l.longname
AND t.tag = 'atag'
WHERE l.location IN ('Japan', 'France', 'Italy')
GROUP BY l.location
ORDER BY FIELD(l.location, 'Japan', 'France', 'Italy')
602392714
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