[英]Count total of each activity type - oracle - sql
我有3種活動類型,需要顯示每個活動有多少人參加。 因此,例如,我需要查詢來顯示:
到目前為止,我已經編寫了以下查詢:
SELECT type_of_activity, COUNT (DISTINCT individual_id)
FROM activities, events, book_activity
WHERE activities.activity_code = events.activity_code
AND events.event_id = book_activity.event_id;
這顯然是錯誤的,並出現錯誤“ not a single group function
”
我需要做的是計算每個ID的每個唯一實例的類型-每個類型的滑雪。 我看過很多資源,但找不到任何示例或幫助
SELECT a.type_of_activity, COUNT(ba.individual_id)
FROM BOOK_ACTIVITY ba
JOIN EVENTS e
ON e.event_id = ba.event_id
JOIN ACTIVITIES a
ON a.activity_code = e.activity_code
GROUP BY a.type_of_activity;
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