Question

我希望根据同一行中的值返回重复的数据行。

请参考下表......

customer | noOfConnections
A        | 1
B        | 1
C        | 2
D        | 1

我想要一些sql来返回...

customer | connectionNumber
A        | 1
B        | 1
C        | 1
C        | 2
D        | 1

有办法吗？

由于

Answer 1

;with  cTE as
(

select   'A' customer, 1 noOfConnections union all
select  'B', 1 union all
select  'C', 2 union all
select  'D', 1 
)
, CTE1 as
(
select customer,noOfConnections from cte where noOfConnections>1
union all
select a.customer,a.noOfConnections-1 from cte A inner join cte1 B 
on a.customer=b.customer and b.noOfConnections=a.noOfConnections

)
select * from cte1 
union all
select * from cte where noOfConnections=1

Answer 2

数字表，yayyy！

搜索脚本。或者here's one I made earlier。

SELECT your_table.customer
     , your_table.noOfConnections
     , numbers.number As connectionNumber
FROM   your_table
 INNER
  JOIN dbo.numbers
    ON numbers.number BETWEEN 1 AND your_table.noOfConnections

Answer 3

试试这个

--Drop table Table1

CREATE TABLE Table1
    ([cust] varchar(1), [cn] int)
;

INSERT INTO Table1
VALUES
    ('A', 1),
    ('B', 1),
    ('C', 1),
    ('C', 2),
    ('D', 1),
    ('E', 4);

with cte as(
    select Max(cn) CN,
                    cust 
    from Table1
    group by cust
    union all 
    select c1.Cn-1 CN,c1.cust from cte c1 join table1 T1 on c1.cust=t1.cust
    where c1.cn-1>0
)
select * from cte
order by cust,cn

Answer 4

具有表值函数的CTE在此处运行良好。只需用您可以遇到的最大数量替换10即可。

WITH q AS
(
    SELECT  1 AS maxNum
    UNION ALL
    SELECT  maxNum + 1
    FROM    q
    WHERE   maxNum < 10
)
SELECT Customer, maxNum as connectionNumber
FROM Customers
CROSS APPLY (SELECT * FROM q WHERE maxNum<=noOfConnections) temp

编辑：您可以返工CTE以从表中提取最大值，请参阅上面的答案：所以这将是我的解决方案：

WITH q AS
(
    SELECT Max(noOfConnections) AS maxNum
    FROM Customers
    UNION ALL
    SELECT  maxNum - 1
    FROM    q
    WHERE   maxNum > 1
)
SELECT Customer, maxNum as connectionNumber
FROM Customers
CROSS APPLY (SELECT * FROM q WHERE maxNum<=noOfConnections) temp

SQL返回X行，具体取决于同一行中的值

4 个答案: