Mysql 我需要计算每个员工每月的平均产量

我需要创建一份报告，显示平均每天至少生产30件的员工

我有两张桌子：

Employees: id, name, surname
Production: id, date_time, id_employee, [..], quantity_produced

员工表中的id=生产表中的id\u员工

---

或

或

---

对于过滤器聚合结果，您需要having子句

SELECT name, surname, Avg(quantity_produced), Month(date_time) Mnth
FROM production 
inner join employees on employees.id = production.id_employee
GROUP BY name, surname, Month(date_time)
having Avg(quantity_produced) > 30 ;

还有一年

SELECT name, surname, Avg(quantity_produced), Month(date_time) Mnth, year(date_time) year
FROM production 
inner join employees on employees.id = production.id_employee
GROUP BY name, surname, Month(date_time), year(date_time) year
having Avg(quantity_produced) > 30 ;

---

在使用月份时，您应该确保也考虑了年份：

SELECT year(p.data_ora) as yyyy, month(p.data_ora) as mm,
       e.name, e.surname, avg(p.quantity_produced),
FROM production p inner join
     employees e
     on e.id = p.id_employee
GROUP BY year(p.data_ora), month(p.data_ora,
         e.name, e.surname
HAVING avg(p.quantity_produced) >= 30
ORDER BY year(p.data_ora), month(p.data_ora),
         e.name, e.surname;

这假设

生产

具有员工每天工作的产量

注:

• 当表引用多个表时，限定所有列引用
• 使用表别名，以便更易于编写和读取查询
• 记住这一年！（当您使用月份时）

---

我很可能会选择下面的问题

但如果没有实例数据和预期结果，很难提出可靠的建议

查询：

SELECT 
    Production.id_employee,
    AVG(Production.quantity_produced)
FROM 
    Production
WHERE
    Production.date_time BETWEEN
                         (LAST_DAY(NOW()) + INTERVAL 1 DAY) - INTERVAL 1 MONTH # first day of current month
                         AND
                         LAST_DAY(NOW()) # last day of current month
GROUP BY 
    Production.id_employee

查询何时需要员工记录：

SELECT 
    Employees.name,
    Employees.surname,
    AVG(Production.quantity_produced)
FROM 
    Production
INNER JOIN 
    Employees ON Production.id_employee = Employees.id
WHERE
    Production.date_time BETWEEN
                         (LAST_DAY(NOW()) + INTERVAL 1 DAY) - INTERVAL 1 MONTH  # first day of current month
                         AND
                         LAST_DAY(NOW()) # last day of current month
GROUP BY 
    Employees.id

注意，上面的查询假设至少有MySQL 5.7.5+和SQL 1999+标准可选特性，称为

看

或者作为相关联的子查询：如果索引正确，这应该是好的

SELECT 
    (SELECT Employees.name FROM Employees.id = Production.id_employee) AS name,
    (SELECT Employees.surname FROM Employees.id = Production.id_employee) AS surname,
    AVG(Production.quantity_produced)
FROM 
    Production
WHERE
    Production.date_time BETWEEN
                         (LAST_DAY(NOW()) + INTERVAL 1 DAY) - INTERVAL 1 MONTH # first day of current month
                         AND LAST_DAY(NOW()) # last day of current month
GROUP BY 
    Production.id_employee

---

您是否需要计算所有年份中所有月份的平均值？？？给定的查询有什么问题？您可以分享哪些功能可以使用，以及您需要帮助的地方吗？公平警告：上述查询假设至少有MySQL 5.7.5+和SQL 1999+标准可选功能，称为。。。请看，我是根据MS SQL Server标准编写的。那么您的SQL应该会失败，因为SQL Server不支持此类查询，因为E.name不在GROUP BY中。。SQL Server不支持功能依赖性非常感谢您指出这一点。你说得对。根据我的理解，如果我们只在这两个地方使用ID（group by和select），那么它的性能会更好。因为大多数时候id是主键（或者你可以说是聚集索引），它会使它更快。写上名字会让事情变得有点慢。你怎么认为。

SELECT 
    Production.id_employee,
    AVG(Production.quantity_produced)
FROM 
    Production
WHERE
    Production.date_time BETWEEN
                         (LAST_DAY(NOW()) + INTERVAL 1 DAY) - INTERVAL 1 MONTH # first day of current month
                         AND
                         LAST_DAY(NOW()) # last day of current month
GROUP BY 
    Production.id_employee

SELECT 
    Employees.name,
    Employees.surname,
    AVG(Production.quantity_produced)
FROM 
    Production
INNER JOIN 
    Employees ON Production.id_employee = Employees.id
WHERE
    Production.date_time BETWEEN
                         (LAST_DAY(NOW()) + INTERVAL 1 DAY) - INTERVAL 1 MONTH  # first day of current month
                         AND
                         LAST_DAY(NOW()) # last day of current month
GROUP BY 
    Employees.id

SELECT 
    (SELECT Employees.name FROM Employees.id = Production.id_employee) AS name,
    (SELECT Employees.surname FROM Employees.id = Production.id_employee) AS surname,
    AVG(Production.quantity_produced)
FROM 
    Production
WHERE
    Production.date_time BETWEEN
                         (LAST_DAY(NOW()) + INTERVAL 1 DAY) - INTERVAL 1 MONTH # first day of current month
                         AND LAST_DAY(NOW()) # last day of current month
GROUP BY 
    Production.id_employee

    I think this should work , can you please try it once. And may be little modification required, Comment here I will try to do the fixes.
  1.Select
         E.id "Employee ID",
         E.name "Employee Name",
         Month(P.date_time) "Month",
         AVG(P.quantity_produced) "Quantity Produced"
    From Employee as E
         Join Production as P on E.id=P. id_employee
    Group by
         E.id,E.name,Month(P.date_time)
    Having Avg(P.quantity_produced) > 30

2.Select
         E.name "Employee Name",
         Month(P.date_time) "Month",
         AVG(P.quantity_produced) "Quantity Produced"
    From Employee as E
         Join Production as P on E.id=P. id_employee
    Group by
         E.name,Month(P.date_time)
    Having Avg(P.quantity_produced) > 30