基于相同的ID

Question

我试图解决的问题加入行的更好的方法是知道密码怎么会经常occure相同registrationid和33以及limitid值5

这是一对夫妇我在SQL数据库表中有以下行：

 id limitid registrationid 
--------------------------------------- 
    113  33    3712 
    114  5    3712 
    116  33    3713 
    117  5    3713 
    1428  33    3714 
    1434  5    3720 

RegistrationId在此表中可以有0,1或2个值。 我要寻找其中regsitrationId有两个值的情况下，并（与registrationid一起）把相应limitid的结果集中，如：

limitid1 limitid2 registrationid 
------------------------------------------ 
      33   5    3712 

为了实现这个目标我使用这个SQL代码：

DECLARE @t TABLE(
    id int NOT NULL, 
    regid int NOT NULL, 
    limitid int not null 
); 
insert into @t 
SELECT Id, RegistrationId, limitid 
FROM  my-table 
WHERE  (LimitId = 33) 
ORDER BY RegistrationId 

DECLARE @t2 TABLE(
    id int NOT NULL, 
    regid int NOT NULL, 
    limitid int not null 
); 
insert into @t2 
SELECT Id, RegistrationId, limitid 
FROM  my-table 
WHERE  (LimitId = 5) 
ORDER BY RegistrationId 

declare @t3 Table(
    regid int NOT NULL, 
    limitid1 int not null, 
    limitid2 int not null 
); 
insert into @t3 
SELECT  t1.RegId, t1.limitid, t2.limitid 
FROM  @t as t1 
join @t2 as t2 
on t1.regid = t2.regid 

select * from @t3 

我的问题：是否有不同的/更好的方法来达到相同的结果？

谢谢！

Answer 1

我不是100％肯定我完全理解你，但你可以实现与输出：

SELECT t1.limitId AS limitid1,t2.limitId AS limitid2, t1.registrationID 
FROM myTable t1 
INNER JOIN myTable t2 ON t1.registrationID = t2.registrationID 
WHERE t1.limitID = 33 
    AND t2.limitID = 5; 

sqlfiddle demo

这给了你limitID1和limitID2的组合和registrationID的它们之间共享。

编辑：

如果你不想让每一个registrationID，你可以得到只有MIN（t1.registrationID）：

SELECT t1.limitId AS limitid1, 
     t2.limitId AS limitid2, 
     MIN(t1.registrationID) AS Num_Records 
FROM myTable t1 
INNER JOIN myTable t2 ON t1.registrationID = t2.registrationID 
WHERE t1.limitID = 33 AND t2.limitID = 5 
GROUP BY t1.limitId,t2.limitId 

sqlfiddle demo