Oracle重複行N次，其中N是列

Question

我是Oracle的新手，我試圖做一些不尋常的事情。鑑於此表和數據，我需要選擇每行，重複的對象，其中DupCount大於1

create table TestTable 
(
    Name  VARCHAR(10), 
    DupCount NUMBER 
) 

INSERT INTO TestTable VALUES ('Jane', 1); 
INSERT INTO TestTable VALUES ('Mark', 2); 
INSERT INTO TestTable VALUES ('Steve', 1); 
INSERT INTO TestTable VALUES ('Jeff', 3); 

期望的結果：

Name  DupCount 
--------- ----------- 
Jane  1 
Mark  2 
Mark  2 
Steve  1 
Jeff  3 
Jeff  3 
Jeff  3 

如果通過一個單一的SELECT語句是不可能的任何有關存儲過程的幫助將不勝感激。

Answer 1

您可以使用分層查詢做到這一點：

SQL Fiddle

查詢1：

WITH levels AS (
    SELECT LEVEL AS lvl 
    FROM DUAL 
    CONNECT BY LEVEL <= (SELECT MAX(DupCount) FROM TestTable) 
) 
SELECT Name, 
     DupCount 
FROM TestTable 
     INNER JOIN 
     levels 
     ON (lvl <= DupCount) 
ORDER BY Name 

Results：

| NAME | DUPCOUNT | 
|-------|----------| 
| Jane |  1 | 
| Jeff |  3 | 
| Jeff |  3 | 
| Jeff |  3 | 
| Mark |  2 | 
| Mark |  2 | 
| Steve |  1 | 

Answer 2

你可以用遞歸cte來做到這一點。它看起來像這樣

with cte as (name, dupcount, temp) 
(
    select name, 
      dupcount, 
      dupcount as temp 
    from testtable 
    union all 
    select name, 
      dupcount, 
      temp-1 as temp 
    from cte 
    where temp > 1 
) 
select name, 
     dupcount 
from cte 
order by name