Sql 什么'；oracle 11g上出现ORA-00979的原因是什么

试图理解SQL中的

groupby

用法

我已经多次遇到这个错误，我可能无法识别核心，以便在以后的时间里解决它

SELECT d.department_name
FROM departments d
JOIN employees e
ON (d.department_id = e.department_id)
GROUP BY d.department_name
HAVING (SELECT COUNT(*) FROM employees) > 5
AND e.commission_pct IS NOT NULL;

ORA-00979:不是表达式分组
97900000-“不是表达式的组”
*原因：
*行动：
第7行第5列出错

您的语法错误，条件应在where子句中，having不应重新选择值

 SELECT d.department_name
 FROM departments d
 JOIN employees e
 ON (d.department_id = e.department_id)
 WHERE e.commission_pct IS NOT NULL
 GROUP BY d.department_name
 HAVING COUNT(*)  > 5 ;

---

请参见

您的语法错误，条件应在where子句中，having不应重新选择值

 SELECT d.department_name
 FROM departments d
 JOIN employees e
 ON (d.department_id = e.department_id)
 WHERE e.commission_pct IS NOT NULL
 GROUP BY d.department_name
 HAVING COUNT(*)  > 5 ;

---

参见

have应该有按其构建方式分组的列。因此，having允许您聚合或操作group by的列。获取group by错误的原因是使用了子查询而不是group by或AGGRATE列

简言之，have与where类似，只是have允许您过滤组的记录，而where用于过滤整个表本身的记录

    SELECT d.department_name
   FROM departments d
    JOIN employees e
    ON (d.department_id = 
      e.department_id)
     Where
      e.commission_pct IS NOT NULL
   GROUP BY d.department_name
    HAVING  COUNT(*) > 5
   ;

---

它的构建方式应该是按它分组的列。因此，having允许您聚合或操作group by的列。获取group by错误的原因是使用了子查询而不是group by或AGGRATE列

简言之，have与where类似，只是have允许您过滤组的记录，而where用于过滤整个表本身的记录

    SELECT d.department_name
   FROM departments d
    JOIN employees e
    ON (d.department_id = 
      e.department_id)
     Where
      e.commission_pct IS NOT NULL
   GROUP BY d.department_name
    HAVING  COUNT(*) > 5
   ;