在oracle中将包含逗号分隔值的两列拆分

Question

我在表中有两列，用逗号分隔值，如何将其拆分为行？

Answer 1

使用递归子查询分解子句和简单的字符串函数：

WITH splits ( id, c1, c2, idx, start_c1, end_c1, start_c2, end_c2 ) AS (
  SELECT id,
         c1,
         c2,
         1,
         1,
         INSTR( c1, ',', 1 ),
         1,
         INSTR( c2, ',', 1 )
  FROM   test_data
UNION ALL
  SELECT id,
         c1,
         c2,
         idx + 1,
         CASE end_c1 WHEN 0 THEN NULL ELSE end_c1 + 1 END,
         CASE end_c1 WHEN 0 THEN NULL ELSE INSTR( c1, ',', end_c1 + 1 ) END,
         CASE end_c2 WHEN 0 THEN NULL ELSE end_c2 + 1 END,
         CASE end_c2 WHEN 0 THEN NULL ELSE INSTR( c2, ',', end_c2 + 1 ) END
  FROM   splits
  WHERE  end_c1 > 0
  OR     end_c2 > 0
)
SELECT id,
       idx,
       CASE end_c1
       WHEN 0
       THEN SUBSTR( c1, start_c1 )
       ELSE SUBSTR( c1, start_c1, end_c1 - start_c1 )
       END AS c1,
       CASE end_c2
       WHEN 0
       THEN SUBSTR( c2, start_c2 )
       ELSE SUBSTR( c2, start_c2, end_c2 - start_c2 )
       END AS c2
FROM   splits s
ORDER BY id, idx;

因此为测试数据：

CREATE TABLE test_data ( id, c1, c2 ) AS
SELECT 1, 'a,b,c,d', 'e,f,g' FROM DUAL UNION ALL
SELECT 2, 'h', 'i' FROM DUAL UNION ALL
SELECT 3, NULL, 'j,k,l,m,n' FROM DUAL;

此输出：

ID | IDX | C1 | C2-：| -：| ：- ：-1 | 1 |一个| Ë1 | 2 | b | F1 | 3 | c | G1 | 4 | d | null2 | 1 | h |一世3 | 1 | 空 | Ĵ3 | 2 | 空 | ķ3 | 3 | 空 |升3 | 4 | 空 |米3 | 5 | 空 | ñ

db <>小提琴here