Question

如果我们想从表1

中表2 的形式获得结果，那么SQL查询应该是什么？

表1：

Type1 | Type2
------|-------
A     |  Dev
B     |  User
C     |  User1
User  |  Dev
User1 |  User
User2 |  User1

表2：

X| Y
------|-------
A     |  Dev
B     |  User
B     |  Dev
C     |  User1
C     |  User
C     |  Dev
User  |  Dev
User1 |  User
User1 |  Dev
User2 |  User1
User2 |  User
User2 |  Dev

Answer 1

在此处使用递归CTE尝试以下脚本。

DECLARE @TABLE  TABLE
(
    Type1   NVARCHAR(10)
    ,Type2  NVARCHAR(10)
)   
INSERT INTO @TABLE
VALUES ('A','Dev'),('B','User'),('C','User1'),('User','Dev'),('User1','User'),('User2','User1')

;WITH CTE
AS
(   SELECT  Type1,Type2
    FROM    @TABLE
    UNION ALL
    SELECT  C.Type1, T.Type2
    FROM    CTE AS  C
        INNER JOIN  @TABLE  AS  T   ON  T.Type1 =   C.Type2
)
SELECT * FROM CTE
ORDER BY Type1,Type2 DESC

输出

Type1   Type2
A       Dev
B       User
B       Dev
C       User1
C       User
C       Dev
User    Dev
User1   User
User1   Dev
User2   User1
User2   User
User2   Dev

Answer 2

select t1.Type1 as X,
       t2.Type2 as Y
from table1 t1
join (select distinct Type2 from table1) t2
   on  t1.Type2 >= t2.Type2
order by x, y desc

执行为：

SQL>select t1.Type1 as X,
SQL&       t2.Type2 as Y
SQL&from table1 t1
SQL&join (select distinct Type2 from table1) t2
SQL&   on  t1.Type2 >= t2.Type2
SQL&order by x, y desc;
X          Y
========== ==========
A          Dev
B          User
B          Dev
C          User1
C          User
C          Dev
User       Dev
User1      User
User1      Dev
User2      User1
User2      User
User2      Dev

                 12 rows found

什么应该是以下结果的SQL查询

2 个答案: