我尝试在regexp_replace函数中使用case语句，因为我想根据不同的情况替换它。 SQL 看起来像这样：
col str for a15
with temp as
(
select 'A*((B*C)+D)' expre1 from dual union all
select 'A*((B*C)-D)' expre1 from dual union all
select '((A*B)+C)*D' expre1 from dual union all
select '((A*B)+C)+D' expre1 from dual union all
select 'A*((B+C)+D)' expre1 from dual union all
select '((A*B)+C)-D' expre1 from dual union all
select 'A*((B+C)-D)' expre1 from dual union all
select '((A*B)+C)/D' expre1 from dual union all
select '((A*B)-C)*D' expre1 from dual union all
select '((A*B)-C)+D' expre1 from dual union all
select 'A*((B-C)+D)' expre1 from dual union all
select 'A*((B-C)-D)' expre1 from dual union all
select '((A*B)-C)-D' expre1 from dual union all
select '((A*B)-C)/D' expre1 from dual union all
select 'A*((B/C)+D)' expre1 from dual union all
select 'A*((B/C)-D)' expre1 from dual union all
select 'A+((B*C)+D)' expre1 from dual union all
select 'A+((B*C)-D)' expre1 from dual union all
select '((A+B)+C)*D' expre1 from dual union all
select 'A+((B+C)+D)' expre1 from dual union all
select '((A+B)+C)+D' expre1 from dual union all
select 'A+((B+C)-D)' expre1 from dual union all
select '((A+B)+C)-D' expre1 from dual union all
select '((A+B)+C)/D' expre1 from dual union all
select '((A+B)-C)*D' expre1 from dual union all
select 'A+((B-C)+D)' expre1 from dual union all
select '((A+B)-C)+D' expre1 from dual union all
select '((A+B)-C)-D' expre1 from dual union all
select 'A+((B-C)-D)' expre1 from dual union all
select '((A+B)-C)/D' expre1 from dual union all
select 'A+((B/C)+D)' expre1 from dual union all
select 'A+((B/C)-D)' expre1 from dual union all
select 'A-((B*C)+D)' expre1 from dual union all
select 'A-((B*C)-D)' expre1 from dual union all
select '((A-B)+C)*D' expre1 from dual union all
select 'A-((B+C)+D)' expre1 from dual union all
select '((A-B)+C)+D' expre1 from dual union all
select 'A-((B+C)-D)' expre1 from dual union all
select '((A-B)+C)-D' expre1 from dual union all
select '((A-B)+C)/D' expre1 from dual union all
select '((A-B)-C)*D' expre1 from dual union all
select 'A-((B-C)+D)' expre1 from dual union all
select '((A-B)-C)+D' expre1 from dual union all
select 'A-((B-C)-D)' expre1 from dual union all
select '((A-B)-C)-D' expre1 from dual union all
select '((A-B)-C)/D' expre1 from dual union all
select 'A-((B/C)+D)' expre1 from dual union all
select 'A-((B/C)-D)' expre1 from dual union all
select 'A/((B*C)+D)' expre1 from dual union all
select 'A/((B*C)-D)' expre1 from dual union all
select '((A/B)+C)*D' expre1 from dual union all
select 'A/((B+C)+D)' expre1 from dual union all
select '((A/B)+C)+D' expre1 from dual union all
select '((A/B)+C)-D' expre1 from dual union all
select 'A/((B+C)-D)' expre1 from dual union all
select '((A/B)+C)/D' expre1 from dual union all
select '((A/B)-C)*D' expre1 from dual union all
select 'A/((B-C)+D)' expre1 from dual union all
select '((A/B)-C)+D' expre1 from dual union all
select 'A/((B-C)-D)' expre1 from dual union all
select '((A/B)-C)-D' expre1 from dual union all
select '((A/B)-C)/D' expre1 from dual union all
select 'A/((B/C)+D)' expre1 from dual union all
select 'A/((B/C)-D)' expre1 from dual
)
select expre1
,regexp_replace(expre1,'\(\(([ABCD])([\*/\+\-])([ABCD])\)([\*/\+\-])([ABCD])\)',
case
when '\4' = '+' or '\4' = '-' then '(\1\2\3\4\5)'
else '((\1\2\3)\4\5)'
end) str
from temp
where regexp_instr(expre1,'\(\(([ABCD])([\*/\+\-])([ABCD])\)([\*/\+\-])([ABCD])\)') > 0;
bug结果如下：
EXPRE1 STR
------------------------- ---------------
A*((B*C)+D) A*((B*C)+D)
A*((B*C)-D) A*((B*C)-D)
((A*B)+C)*D ((A*B)+C)*D
((A*B)+C)+D ((A*B)+C)+D
A*((B+C)+D) A*((B+C)+D)
((A*B)+C)-D ((A*B)+C)-D
A*((B+C)-D) A*((B+C)-D)
看起来代码“when ' '”被视为字符串' '而不是正则表达式。我的目标是删除括号。那么，如何修改呢？
也许无需正则表达式即可完成。使用您的样本数据 - 像这样
Select EXPRE1,
Case When Instr(EXPRE1, '*') = 0 And Instr(EXPRE1, '/') = 0
Then '(' || Replace(Replace(EXPRE1, '(', ''), ')', '') || ')'
When SubStr(EXPRE1, 4, 1) In('+', '-') And Instr(EXPRE1, '*', 1, 1) = Length(EXPRE1) - 1 And Instr(EXPRE1, '/') = 0
Then '(' ||
Replace(
Replace(Replace(Replace(Replace(EXPRE1, '(', ''), ')', ''), ')+', '+'), ')-', '-')
, '*', ')*')
When Instr(EXPRE1, '*', 1, 1) = 2 And Instr(EXPRE1, '*', 1, 2) = 0 And Instr(EXPRE1, '/') = 0
Then SubStr(EXPRE1, 1, 2) || '(' || Replace(Replace(SubStr(EXPRE1, 3), '(', ''), ')', '') || ')'
When Instr(EXPRE1, '*', 1, 1) < Length(EXPRE1) - 1 And Instr(EXPRE1, '/') = 0
Then EXPRE1
--
When SubStr(EXPRE1, 4, 1) In('+', '-') And Instr(EXPRE1, '/', 1, 1) = Length(EXPRE1) - 1 And Instr(EXPRE1, '*') = 0
Then '(' ||
Replace(
Replace(Replace(Replace(Replace(EXPRE1, '(', ''), ')', ''), ')+', '+'), ')-', '-')
, '/', ')/')
When Instr(EXPRE1, '/', 1, 1) = 2 And Instr(EXPRE1, '/', 1, 2) = 0 And Instr(EXPRE1, '*') = 0
Then SubStr(EXPRE1, 1, 2) || '(' || Replace(Replace(SubStr(EXPRE1, 3), '(', ''), ')', '') || ')'
--
When Length(EXPRE1) - Length(Replace(EXPRE1, '*')) > 1 OR Length(EXPRE1) - Length(Replace(EXPRE1, '/')) > 1
Then EXPRE1
Else '((' ||
SubStr(Replace(EXPRE1, '((', ''), 1, InStr(Replace(EXPRE1, '((', ''), ')', 1, 1)) ||
SubStr(Replace(EXPRE1, '((', ''), InStr(Replace(EXPRE1, '((', ''), ')', 1, 1) + 1)
End "STR"
From temp
/* R e s u l t :
EXPRE1 STR
----------- ----------------------------------------
A*((B*C)+D) A*((B*C)+D)
A*((B*C)-D) A*((B*C)-D)
((A*B)+C)*D ((A*B)+C)*D
((A*B)+C)+D ((A*B)+C)+D
A*((B+C)+D) A*(B+C+D)
((A*B)+C)-D ((A*B)+C)-D
A*((B+C)-D) A*(B+C-D)
((A*B)+C)/D ((A*B)+C)/D
((A*B)-C)*D ((A*B)-C)*D
((A*B)-C)+D ((A*B)-C)+D
A*((B-C)+D) A*(B-C+D)
A*((B-C)-D) A*(B-C-D)
((A*B)-C)-D ((A*B)-C)-D
((A*B)-C)/D ((A*B)-C)/D
A*((B/C)+D) ((A*B/C)+D)
A*((B/C)-D) ((A*B/C)-D)
A+((B*C)+D) A+((B*C)+D)
A+((B*C)-D) A+((B*C)-D)
((A+B)+C)*D (A+B+C)*D
A+((B+C)+D) (A+B+C+D)
((A+B)+C)+D (A+B+C+D)
A+((B+C)-D) (A+B+C-D)
((A+B)+C)-D (A+B+C-D)
((A+B)+C)/D (A+B+C)/D
((A+B)-C)*D (A+B-C)*D
A+((B-C)+D) (A+B-C+D)
((A+B)-C)+D (A+B-C+D)
((A+B)-C)-D (A+B-C-D)
A+((B-C)-D) (A+B-C-D)
((A+B)-C)/D (A+B-C)/D
A+((B/C)+D) ((A+B/C)+D)
A+((B/C)-D) ((A+B/C)-D)
A-((B*C)+D) A-((B*C)+D)
A-((B*C)-D) A-((B*C)-D)
((A-B)+C)*D (A-B+C)*D
A-((B+C)+D) (A-B+C+D)
((A-B)+C)+D (A-B+C+D)
A-((B+C)-D) (A-B+C-D)
((A-B)+C)-D (A-B+C-D)
((A-B)+C)/D (A-B+C)/D
((A-B)-C)*D (A-B-C)*D
A-((B-C)+D) (A-B-C+D)
((A-B)-C)+D (A-B-C+D)
A-((B-C)-D) (A-B-C-D)
((A-B)-C)-D (A-B-C-D)
((A-B)-C)/D (A-B-C)/D
A-((B/C)+D) ((A-B/C)+D)
A-((B/C)-D) ((A-B/C)-D)
A/((B*C)+D) ((A/B*C)+D)
A/((B*C)-D) ((A/B*C)-D)
((A/B)+C)*D ((A/B)+C)*D
A/((B+C)+D) A/(B+C+D)
((A/B)+C)+D ((A/B)+C)+D
((A/B)+C)-D ((A/B)+C)-D
A/((B+C)-D) A/(B+C-D)
((A/B)+C)/D ((A/B)+C)/D
((A/B)-C)*D ((A/B)-C)*D
A/((B-C)+D) A/(B-C+D)
((A/B)-C)+D ((A/B)-C)+D
A/((B-C)-D) A/(B-C-D)
((A/B)-C)-D ((A/B)-C)-D
((A/B)-C)/D ((A/B)-C)/D
A/((B/C)+D) A/((B/C)+D)
A/((B/C)-D) A/((B/C)-D) */