Question

我有四张桌子。我需要从所有这些数据中获取数据。表'Tenancy_histories'包含move_in_date，move_out_date，rent列。 '个人资料'包含first_name，last_name，email，profile_id等。'推介'包含referrer_bonus_amount和类似的其他数据。

最重要的是，它包含特定profile_id所引用的引荐数，该引用数是'referrer_id（与profile id相同）列中该profile_id的出现次数。 'Houses'包含租户占用的房屋详细信息。表'众议院'和'个人资料'没有直接关联，而是通过表格'Tenancy_histories'

进行关联

我需要写一个查询来获取尚未提及过一次的租户的姓名，联系方式，城市和房屋详细信息。

我尝试了类似这样的东西，但没有得到所需的输出但没有得到任何错误

SELECT
    pr.first_name + ' ' + pr.last_name AS full_name, pr.phone, 
    pr.[city(hometown)], hs.bhk_details 
FROM
    Profiles pr  
INNER JOIN 
    Tenancy_histories th ON pr.profile_id = th.profile_id 
INNER JOIN 
    Houses hs ON th.house_id = hs.house_id 
INNER JOIN 
    Referrals rf ON pr.profile_id = rf.[referrer_id(same as profile id)] 
WHERE 
    pr.profile_id NOT IN (SELECT [referrer_id(same as profile id)] 
                          FROM Referrals)

Answer 1

试试这个：

select full_name , phone,[city(hometown)], bhk_details ,profile_id 
from (
select p.full_name , p.phone,p.[city(hometown)], p.bhk_details ,p.profile_id
from (
select pr.first_name+' '+pr.last_name as full_name, pr.phone, pr.[city(hometown)], hs.bhk_details ,pr.profile_id
from Profiles pr 
INNER JOIN 
Tenancy_histories th 
on pr.profile_id = th.profile_id 
INNER JOIN 
Houses hs 
on th.house_id = hs.house_id 
) as p
left join
Referrals rf 
on p.profile_id = rf.[referrer_id(same as profile id)] 
where rf.[referrer_id(same as profile id)] is null
) as p_r

Answer 2

只需删除INNER JOIN到引荐表就可以了解

SELECT
    pr.first_name + ' ' + pr.last_name AS full_name, 
    pr.phone, 
    pr.[city(hometown)], 
    hs.bhk_details 
FROM
    Profiles pr  
INNER JOIN 
    Tenancy_histories th ON pr.profile_id = th.profile_id 
INNER JOIN 
    Houses hs ON th.house_id = hs.house_id 
WHERE 
    pr.profile_id NOT IN (SELECT [referrer_id(same as profile id)] 
                          FROM Referrals)

Answer 3

带有子查询的

NOT IN很危险。如果子查询中的任何行返回NULL值，则不会返回任何行。

除了将inner join移至referrals之外，我还建议您将比较更改为使用NOT EXISTS：

WHERE NOT EXISTS (SELECT 1
                  FROM referrals
                  WHERE pr.profile_id = r.[referrer_id(same as profile id)] 
                 );

另一种方法是使用LEFT JOIN到referrals，然后检查是否匹配：

SELECT pr.first_name + ' ' + pr.last_name AS full_name, pr.phone, 
       pr.[city(hometown)], hs.bhk_details 
FROM Profiles pr INNER JOIN 
     Tenancy_histories th
     ON pr.profile_id = th.profile_id INNER JOIN 
     Houses hs
     ON th.house_id = hs.house_id LEFT JOIN 
     Referrals rf
     ON pr.profile_id = rf.[referrer_id(same as profile id)] 
WHERE rf.[referrer_id(same as profile id)] IS NULL;

关于INNER JOIN的Where子句

3 个答案: