为什么我在群组中遇到语法错误？

我已经创建了下面的查询，但是当我运行它时，我在GROUP BY子句中得到语法错误，但是当我删除它时，PostgreSQL给了我需要将t.bsn添加到GROUP BY子句的错误。我该如何解决这个错误？为什么我在群组中遇到语法错误？

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;

来源

2016-12-28 Ino van den Berg

'集团BY'到来之前'HAVING'。但是，查询还存在其他大问题。您正在创建这四张表的笛卡尔积。作为一个经验法则，逗号应该永远不会被放在'FROM'子句中（这种做法现在已被弃用** 25年**）。改用显式的'JOIN'语法。 – Siyual

根据SQL标准HAVING条款应该来后GROUP BY;你的是之前。

代码：

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;

预计：

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实例 - http://www.w3schools.com/sql/sql_having.asp

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

来源

2016-12-28 19:23:54 OShadmon

为什么我在群组中遇到语法错误？

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