测试数据:
[sql] view plaincopy
- CREATE TABLE t (str VARCHAR2(30));
- INSERT INTO t VALUES ( ‘X,Y,Z‘ );
- INSERT INTO t VALUES ( ‘XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG‘ );
- commit;
--1、multiset 8i之后都支持
[sql] view plaincopy
- SQL> CREATE OR REPLACE TYPE number_ntt AS TABLE OF NUMBER;
- 2 /
- Type created
- SQL> col value for a20
- SQL>
- SQL> with ilv as
- 2 (select str || ‘,‘ as str,
- 3 (length(str) - length(replace(str, ‘,‘))) + 1 as no_of_elements
- 4 from t)
- 5 select a.str, regexp_substr(a.str, ‘[^,]+‘, 1, b.column_value) value
- 6 from ilv a, table(cast(multiset (select rownum rn
- 7 from dual
- 8 connect by rownum <= a.no_of_elements) as number_ntt)) b;
- STR VALUE
- ------------------------------- --------------------
- X,Y,Z, X
- X,Y,Z, Y
- X,Y,Z, Z
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG, XXX
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG, Y
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG, ZZ
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG, AAAAA
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG, B
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG, CCC
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG, D
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG, E
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG, F
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG, GGG
- 13 rows selected
- SQL>
2、自关联connect by 10g之后
[sql] view plaincopy
- SQL> select str,
- 2 regexp_substr(str, ‘[^,]+‘, 1, level) value
- 3 from t
- 4 connect by
- 5 str = prior str
- 6 and instr(str||‘,‘, ‘,‘, 1, level) > 0
- 7 and prior dbms_random.value is not null;
- STR VALUE
- ------------------------------ --------------------
- X,Y,Z X
- X,Y,Z Y
- X,Y,Z Z
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG XXX
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG Y
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG ZZ
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG AAAAA
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG B
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG CCC
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG D
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG E
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG F
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG GGG
- 13 rows selected
- SQL>
3、自关联,非CONNECT BY方式
[sql] view plaincopy
- SQL> with tmp as (
- 2 select t.*,
- 3 length(str)-length(regexp_replace(str, ‘,‘, ‘‘))+1 len
- 4 from t
- 5 )
- 6 select a.*, regexp_substr(str, ‘[^,]+‘, 1, rn) value
- 7 from tmp a, (select rownum rn from dual connect by level <= (select max(len) from tmp x)) b
- 8 where a.len>=b.rn
- 9 order by 1;
- STR LEN VALUE
- ------------------------------ ---------- --------------------
- X,Y,Z 3 Y
- X,Y,Z 3 Z
- X,Y,Z 3 X
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG 10 GGG
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG 10 B
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG 10 CCC
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG 10 D
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG 10 E
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG 10 F
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG 10 ZZ
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG 10 Y
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG 10 XXX
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG 10 AAAAA
- 13 rows selected
- SQL>
4、Model子句,复杂度有点小高
[sql] view plaincopy
- SQL> col single_element for a15
- SQL>
- SQL> with ilv as
- 2 (select str as orig_str,
- 3 ‘,‘ || str || ‘,‘ as mod_str,
- 4 1 as start_pos,
- 5 length(str) as end_pos,
- 6 (length(str) - length(replace(str, ‘,‘))) + 1 as element_count,
- 7 0 as element_no,
- 8 rownum as rn
- 9 from t)
- 10 select orig_str as original_string,
- 11 substr(mod_str, start_pos, end_pos - start_pos) as single_element,
- 12 element_no,
- 13 element_count
- 14 from (select *
- 15 from ilv
- 16 model partition by(rn, orig_str, mod_str)
- 17 dimension by(element_no)
- 18 measures(start_pos, end_pos, element_count)
- 19 rules iterate(2000)
- 20 until(iteration_number + 1 = element_count[0])(
- 21 start_pos[iteration_number + 1] = instr(cv(mod_str), ‘,‘, 1, cv(element_no)) + 1,
- 22 end_pos[iteration_number + 1] = instr(cv(mod_str), ‘,‘, 1, cv(element_no) + 1)
- 23 )
- 24 )
- 25 where element_no != 0
- 26 order by mod_str, element_no;
- ORIGINAL_STRING SINGLE_ELEMENT ELEMENT_NO ELEMENT_COUNT
- ------------------------------ --------------- ---------- -------------
- X,Y,Z X 1
- X,Y,Z Y 2
- X,Y,Z Z 3
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG XXX 1
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG Y 2
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG ZZ 3
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG AAAAA 4
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG B 5
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG CCC 6
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG D 7
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG E 8
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG F 9
- XXX,Y,ZZ,AAAAA,B,CCC,D,E,F,GGG GGG 10
- 13 rows selected
- SQL>
其他可以编写自定义函数进行拆分
时间: 2024-11-04 15:56:41