多个逗号分隔的列表到列

Question

我正在尝试将列中的逗号分隔列表拆分为不同的行。例如：

with testdata(vala,valb,valc) as(
select
    '1,2,3,4' as vala,
    '5,6,7,8' as valb,
    '9,10,11' as valc
from dual)

使用上面的表格，我试图以 vala、valb 和 valc 是列的形式获取值，不同的逗号分隔值是行。如下图所示：

我已经查看了https://lalitkumarb.wordpress.com/2014/12/02/split-comma-delimited-string-into-rows-in-oracle/ 和https://blogs.oracle.com/aramamoo/how-to-split-comma-separated-string-and-pass-to-in-clause-of-select-statement，但我似乎无法应用所描述的方法，因为我有更多列...

我需要进行这种转换的原因是为了在查询的下方使用 IN 表达式中的这些值。

Answer 1

无论“高度”列如何，这都应该有效。

with testdata(vala, valb, valc) as(
   select '1,2,3,4' as vala
         ,'5,6,7,8' as valb
         ,'9,10,11' as valc
     from dual
)
select regexp_substr(vala,'[^,]+', 1, level) as vala -- Pick the 
      ,regexp_substr(valb,'[^,]+', 1, level) as valb -- value at this 
      ,regexp_substr(valc,'[^,]+', 1, level) as valc -- position or null
  from testdata
  connect by regexp_substr(vala,'[^,]+', 1, level) is not null -- Generate one row if 
          or regexp_substr(valb,'[^,]+', 1, level) is not null -- any of the positions
          or regexp_substr(valc,'[^,]+', 1, level) is not null -- would have a value

Answer 2

试试这个：

with testdata(vala,valb,valc)
 as(
select
    '1,2,3,4' as vala,
    '5,6,7,8' as valb,
    '9,10,11' as valc
from dual)
,
main as (
select rownum rn, 
regexp_substr(vala,'[^,]+', 1, level) data from
testdata
connect by  regexp_substr(vala,'[^,]+', 1, level) is not null
),
sub as (
select  rownum rn, 
regexp_substr(valb,'[^,]+', 1, level)data from
testdata
connect by  regexp_substr(valb,'[^,]+', 1, level) is not null
),
sub2 as (
select  rownum rn, 
regexp_substr(valc,'[^,]+', 1, level)data from
testdata
connect by  regexp_substr(valc,'[^,]+', 1, level) is not null
)
select 
main.data,
sub.data,
sub2.data
 from
main 
full outer join
sub on main.rn=sub.rn
full outer join
sub2 on main.rn=sub2.rn

Answer 3

一种只使用简单字符串函数（而不是慢速正则表达式）的解决方案，不需要任何连接，还可以处理多个输入行：

Oracle 设置：

CREATE TABLE testdata (vala, valb, valc) AS
  SELECT '1,2,3,4','5,6,7,8', '9,10,11' FROM DUAL UNION ALL
  SELECT '12', '13,14,15,16', '' FROM DUAL;

查询：

WITH data ( vala, valb, valc, starta, startb, startc, enda, endb, endc, rn, idx ) AS (
  SELECT vala,
         valb,
         valc,
         1,
         1,
         1,
         INSTR( vala, ',', 1 ),
         INSTR( valb, ',', 1 ),
         INSTR( valc, ',', 1 ),
         ROWNUM,
         1
  FROM   testdata
UNION ALL
  SELECT vala,
         valb,
         valc,
         CASE WHEN enda = 0 THEN 0 ELSE enda + 1 END,
         CASE WHEN endb = 0 THEN 0 ELSE endb + 1 END,
         CASE WHEN endc = 0 THEN 0 ELSE endc + 1 END,
         CASE WHEN enda = 0 THEN 0 ELSE INSTR( vala, ',', enda + 1 ) END,
         CASE WHEN endb = 0 THEN 0 ELSE INSTR( valb, ',', endb + 1 ) END,
         CASE WHEN endc = 0 THEN 0 ELSE INSTR( valc, ',', endc + 1 ) END,
         rn,
         idx + 1
  FROM   data
  WHERE  enda > 0
  OR     endb > 0
  OR     endc > 0
)
SELECT CASE
       WHEN starta = 0 THEN NULL
       WHEN enda   = 0 THEN SUBSTR( vala, starta )
                       ELSE SUBSTR( vala, starta, enda - starta )
       END AS vala,
       CASE
       WHEN startb = 0 THEN NULL
       WHEN endb   = 0 THEN SUBSTR( valb, startb )
                       ELSE SUBSTR( valb, startb, endb - startb )
       END AS valb,
       CASE
       WHEN startc = 0 THEN NULL
       WHEN endc   = 0 THEN SUBSTR( valc, startc )
                       ELSE SUBSTR( valc, startc, endc - startc )
       END AS valc
FROM   data
ORDER BY rn, idx;

输出：

瓦拉 |阀 | VALC :--- | :--- | :--- 1 | 5 | 9 2 | 6 | 10 3 | 7 | 11 4 | 8 | 空 12 | 13 | 空 空 | 14 | 空 空 | 15 | 空 空 | 16 | 空

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