爲什麼我在羣組中遇到語法錯誤？

我已經創建了下面的查詢，但是當我運行它時，我在GROUP BY子句中得到語法錯誤，但是當我刪除它時，PostgreSQL給了我需要將t.bsn添加到GROUP BY子句的錯誤。我該如何解決這個錯誤？爲什麼我在羣組中遇到語法錯誤？

SELECT t.bsn 
FROM teachers t, designes d, students s, course c, teaches lg 
WHERE c.course_follower = s.class AND t.bsn = lg.bsn AND d.course_code = c.course_code AND d.bsn = t.bsn AND s.class = lg.class 
HAVING t.salary = (2000 + (t.scale * 200) + ((t.scale - 10) * 300) + (100 * (COUNT(d.course_code) * (1.0 + (0.1 * COUNT(s.student_id)))) + (50 * c.amount_of_assignments))) 
GROUP BY t.bsn;

來源

2016-12-28 Ino van den Berg

'集團BY'到來之前'HAVING'。但是，查詢還存在其他大問題。您正在創建這四張表的笛卡爾積。作爲一個經驗法則，逗號應該永遠不會被放在'FROM'子句中（這種做法現在已被棄用** 25年**）。改用顯式的'JOIN'語法。 – Siyual

根據SQL標準HAVING條款應該來後GROUP BY;你的是之前。

代碼：

SELECT 
     t.bsn 
FROM 
     teachers t, designes d, students s, course c, teaches lg 
WHERE 
     c.course_follower = s.class AND 
     t.bsn = lg.bsn AND 
     d.course_code = c.course_code AND 
     d.bsn = t.bsn AND 
     s.class = lg.class 
HAVING 
     t.salary = (2000 + (t.scale * 200) + ((t.scale - 10) * 300) + (100 * (COUNT(d.course_code) * (1.0 + (0.1 * COUNT(s.student_id)))) + (50 * c.amount_of_assignments))) 
GROUP BY 
     t.bsn;

預計：

SELECT 
     t.bsn 
FROM 
     teachers t, designes d, students s, course c, teaches lg 
WHERE 
     c.course_follower = s.class AND 
     t.bsn = lg.bsn AND 
     d.course_code = c.course_code AND 
     d.bsn = t.bsn AND 
     s.class = lg.class 
GROUP BY 
     t.bsn 
HAVING 
     t.salary = (2000 + (t.scale * 200) + ((t.scale - 10) * 300) + (100 * (COUNT(d.course_code) * (1.0 + (0.1 * COUNT(s.student_id)))) + (50 * c.amount_of_assignments)));

通用SQL實例 - http://www.w3schools.com/sql/sql_having.asp

PostgreSQL的SQL實例 - https://www.postgresql.org/docs/current/static/tutorial-agg.html

來源

2016-12-28 19:23:54 OShadmon

爲什麼我在羣組中遇到語法錯誤？

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