asked on

How to get this query ?

Hi Expert,
I am using oracle 11.1.2.0

below is my table

create table sample_test(e_id number(10), e_name varchar2(4000));

insert into SAMPLE_TEST (E_ID,E_NAME) values (103664,'XYZ., Ltd.');
insert into sample_test (e_id,e_NAME) values (103665,'XYZ., Ltd.!@#$%^&*()_+=-{}][|\'';":/?.>,<');

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Query:

select * from  SAMPLE_TEST
where id in (103664,
 103665)
and regexp_instr(E_NAME
                    ,nvl(:Name
                        ,E_NAME)
                    ,1
                    ,1
                    ,1
                    ,'im') > 0;

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when i am running above query(i am passing null value in parameter) , i am getting below error

ORA-12726: unmatched bracket in regular expression
12726. 00000 - "unmatched bracket in regular expression"
*CAUSE: the Regular Expression Did Not Have Balanced Brackets.
*Action: Ensure the brackets are correctly balanced.

Regards
Thomos

ASKER CERTIFIED SOLUTION

slightwv (䄆 Netminder)

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Sean Stuber

change this

'XYZ., Ltd.!@#$%^&*()_+=-{}][|\'';":/?.>,<'

to this

'XYZ., Ltd.!@#$%^&*()_+=-{}]\[|\'';":/?.>,<'

the problem is the [ which starts a list expression, if you don't intend to create one then you'll need to escape it with the slash

or, more likely, since your NVL looks like you are trying to do a wild card self-match then try this instead and then you won't have to modify your data

SELECT *
FROM sample_test
WHERE e_id IN (103664, 103665)
AND REGEXP_INSTR(
e_name,
NVL( :name, '.'),
1,
1,
1,
'im'
) > 0;

Sean Stuber

another option, check for null explicitly outside of the regexp function

SELECT *
FROM sample_test
WHERE e_id IN (103664, 103665)
AND ( :name IS NULL
OR REGEXP_INSTR(
e_name,
:name,
1,
1,
1,
'im'
) > 0)

Sean Stuber

And one more suggestion, rather than using regexp_instr, you might want to try regexp_like for a little simpler syntax

SELECT *
FROM sample_test
WHERE e_id IN (103664, 103665) AND ( :name IS NULL OR REGEXP_LIKE(e_name, :name, 'im'))

Note - both this suggestion and the previous one with the external NULL check should be more efficient but have the side effect that they will match NULL e_names as well which the "." version I suggested first will not.

Assuming your e_names are not null, then they are all functionally equivalent

Sean Stuber

one more thing that occured to me

searching mid-string is not an efficient operation because it's not something you can build a normal index for.

If your data is big, you might want to look into using a text index and changing the query to use CONTAINS.

CONTAINS isn't the same thing as a regular expression parser but it could give better performance for basic substring searches

deve_thomos

ASKER

Thanks lot....

Sean Stuber

are you sure you want to try to modify your data?

adding the slash in this one example fixes that one row.

if you have other characters, for example the "." following "Ltd." that period is not actually a period for the purposes of your matching. It's really a wild card

Is that really what you intended? If not, then you probably don't want to go with a row-at-a-time data fix strategy. Instead, try fixing the query with one of the options suggested.

or, maybe I'm misunderstanding what you were really looking for because the accepted answer does not seem correct for a real-world solution.

Sean Stuber

Based on your coworker's question here :

https://www.experts-exchange.com/questions/28511647/How-to-get-this-query.html

It looks like you two are pursuing CONTAINS rather than corrupting your data as a solution.

That's probably a good idea but it would indicate this question was closed improperly