Question

SQL帮助：我有一份服务时间为六年的汽车列表，我需要获取7月13日之前服务的汽车数据，此后不再提供服务

SELECT j.customer_id, m.name,j.car_id, c.model, c.reg_num, c.chassis_num, c.vin_num, c.engine_num, j.id AS jobcard_id, j.raw_jobcard_id, j.workshop_id, l.name AS workshop_name, j.jobcard_num, j.bill_date AS jobcard_date 
FROM jobcards j 
LEFT JOIN cars c ON j.car_id = c.id 
LEFT JOIN customers m ON j.customer_id = m.id 
LEFT JOIN locations l ON j.workshop_id = l.id 
WHERE j.bill_date < '2013-07-01' 
GROUP BY j.car_id

Answer 1

您可以使用以下方式获取汽车列表：

select j.car_id
from jobcards j
group by j.car_id
having max(j.bill_date) < '2013-07-01';

如果您想要问题中的所有细节，那么每辆车需要多行。您可以使用join，exists或in来实现此目的：

SELECT j.customer_id, m.name, j.car_id, c.model, c.reg_num, c.chassis_num, 
       c.vin_num, c.engine_num, j.id AS jobcard_id, j.raw_jobcard_id, 
       j.workshop_id, l.name AS workshop_name, j.jobcard_num,
       j.bill_date AS jobcard_date 
FROM jobcards j JOIN
     cars c
     ON j.car_id = c.id JOIN
     customers m
     ON j.customer_id = m.id JOIN
     locations l
     ON j.workshop_id = l.id 
WHERE c.id IN (select j.car_id
               from jobcards j
               group by j.car_id
               having max(j.bill_date) < '2013-07-01'
              )
ORDER BY c.id;

我不明白为什么LEFT JOIN在这种情况下是必要的。

Answer 2

SELECT DISTINCT carName, .... 
    FROM table
    WHERE serviceDate < '2016-07-13' and serviceDate >= DATEADD(year,-6,GETDATE())

SQL Query使用日期

2 个答案: