将字符串拆分成行Oracle SQL [英] Split String into rows Oracle SQL

问题描述

在搜索了论坛之后，我提出了以下内容，但是它不起作用:/

After searching the forums I have come up with the following but its not working :/

我有一张桌子，上面有；

I have a table with the following;

ID |   Strings     
123|   abc fgh dwd   
243|   dfs dfd dfg  
353|   dfs  
424|   dfd dfw  
523|    
.  
.  
. 

请不要让大约有20,000行，我的另一选择是编写一个存储过程来做到这一点...基本上，我需要将字符串分开，以便每个这样的行都有

Please not that there is around 20,000 rows my other option is to write a stored procedure to do this ...Basically I need to split the strings up so there is a row for each one like this

ID |  Strings  
123| abc  
123| fgh  
123| dwd  
243| dfs  

以此类推...

这就是我所拥有的.

create table Temp AS   
SELECT ID, strings   
From mytable;  

SELECT DISTINCT ID, trim(regexp_substr(str, '[^ ]+', 1, level)) str  
FROM (SELECT ID, strings str FROM temp) t  
CONNECT BY instr(str, ' ', 1, level -1) >0  
ORDER BY ID;  

感谢您的帮助

推荐答案

这应该可以解决问题:

SELECT DISTINCT ID, regexp_substr("Strings", '[^ ]+', 1, LEVEL)
FROM T
CONNECT BY regexp_substr("Strings", '[^ ]+', 1, LEVEL) IS NOT NULL
ORDER BY ID;

请注意我也如何在connect by子句中使用regexp_substr.这是为了处理多个空格的情况.

Notice how I used regexp_substr in the connect by clause too. This is to deal with the case of multiple spaces.

如果每行项目数的上限是可预测的，则可能需要将上面的递归查询的性能与简单的CROSS JOIN进行比较:

If you have a predictable upper bound on the number of items per line, it might worth comparing the performances of the recursive query above with a simple CROSS JOIN:

WITH N as (SELECT LEVEL POS FROM DUAL CONNECT BY LEVEL < 10)
--                                                       ^^
--                                                 up to 10 substrings
SELECT ID, regexp_substr("Strings", '[^ ]+', 1, POS)
FROM T CROSS JOIN N
WHERE regexp_substr("Strings", '[^ ]+', 1, POS) IS NOT NULL
ORDER BY ID;

请参见 http://sqlfiddle.com/#!4/444e3/1 进行现场演示

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