检查教练的可用性

Question

教练表：

巡回表：

创建一个查询，显示给定日期的可用教练列表
我坚持这个查询，我不知道如何继续：

SELECT
    c.coachID,
    c.coachNo
FROM 
    Tour t 
    inner join Coach c 
        on t.coachID=c.coachID 
WHERE 
    '10/01/2016' BETWEEN startDate AND (DATEADD(DAY,tourDuration,startDate)) 

输出：

coachID|coachNo
1      |WKS5623

Answer 1

我们可以通过以下方式获得可用的教练

1. 找出现在正在巡回演出的教练

   SELECT DISTINCT CoachID FROM Tour WHERE '10/01/2016' BETWEEN startDate AND (DATEADD(DAY, tourDuration, startDate))

2. 让那些不在教练名单中的教练现在参加巡回赛

   SELECT CoachId, CoachNo FROM Coach WHERE CoachId NOT IN ( SELECT DISTINCT CoachID FROM Tour WHERE '10/01/2016' BETWEEN startDate AND (DATEADD(DAY, tourDuration, startDate)) )

希望它可以帮助你。