Question

说我有下表：医生和工作日：

 DocNumbers  | idNum  
  118        | 11    
  119        | 12      
  120        | 13       
  121        | 14       
  122        | 15

注意：医生可以在几个不同的工作日工作。

 DocNum  | Workday    |AmountOfHours |
  118    |   1        |     8        |
  118    |   3        |     9        |
  120    |   1        |     6        |
  121    |   3        |     5        | 
  122    |   4        |     7        |

我想创建一个新表，其中包含在第1天和第3天工作的所有医生的ID - 这意味着我将获得一个仅包含118的表。

到目前为止我已经：

SELECT distinct Doctors.doctorNumber, idNum
FROM Doctors, Workdays
WHERE Workdays.dayInWeek in (1,3)
AND Workdays.doctorNumber=Doctors.doctorNumber

但似乎我得到的结果与120和121无关。所以'IN'更像是'OR'。似乎找不到'和'的等价？

Answer 1

如果您加入Workdays表两次，这很容易，每天要检查一次：

select Doctors.DocNumbers, Doctors.idNum
from Doctors
inner join Workdays as Workdays1 on Workdays1.DocNum = Doctors.DocNumbers and Workdays1.Workday = 1
inner join Workdays as Workdays3 on Workdays3.DocNum = Doctors.DocNumbers and Workdays3.Workday = 3;

http://www.sqlfiddle.com/#!2/4c530/3

Answer 2

使用简单连接尝试此操作

SELECT DISTINCT w.`DocNum`, d.idNum
FROM doctors d
LEFT JOIN  Workdays w ON(d.`DocNumbers`=w.`DocNum`)
LEFT JOIN  Workdays ww ON(d.`DocNumbers`=ww.`DocNum`)
WHERE w.`Workday` = 1 AND ww.`Workday` =3

See fiddle here

这是另一种做同样的方式

SELECT  w.`DocNum`, d.idNum
FROM doctors d
LEFT JOIN  Workdays w ON(d.`DocNumbers`=w.`DocNum`)
GROUP BY d.`DocNumbers`
HAVING GROUP_CONCAT(w.`Workday`  SEPARATOR ',')= '1,3'

See fiddle here

同时选择两个条件

2 个答案: