Question

我在oracle中有下表。版本9i

Num          count

123              1
345              4
455              3
234              2
542              1

我正在尝试编写一个select查询，它给出了以下输出。

每个号码都应显示其计数次数。如果我使用函数，这可以实现吗？我不允许创建任何临时表。

我知道我必须使用循环序列然后使用UNION ALL但不知道如何实现它。我试过这个

select Num from <table> where count=1
union all
// what fits here?

Answer 1

这可以使用伪列LEVEL和Correlated Query来重复数字计数次数...

尝试以下查询

select num from (select distinct num,level,ROWID as RD
from table a
connect by level<= (select count from table b where a.num=b.num))
order by rd;

Answer 2

试试这个

SELECT A.NUM
FROM Test A
INNER JOIN (SELECT ROWNUM RN FROM dual connect by level < 100) B 
ON B.rn <= A.count
order by A.NUM;

SQL DEMO

Answer 3

WITH cte ("Num", "count") 
AS 
(
    SELECT "Num", "count" FROM TableName
    UNION ALL
    SELECT "Num", "count" - 1  FROM cte WHERE "count" > 1
)
SELECT "Num" 
FROM   cte
ORDER  BY "Num"

SQLFiddle Demo

Answer 4

如果您使用11gR2，可以这样做：

with t(num, i) as
(
  select num, count from tab1 union all
  select num, i-1
  from t
  where i >1
  )    
select num from t
order by num;

Here is a sqlfiddle demo

在oracle select语句中循环和union all

4 个答案: