Why doesn't LIKE work with wildcard having % at the beginning?


You might have a problem like this:

CREATE TABLE t1 ( c1 CHAR(5) );
COMMIT;

INSERT INTO t1 VALUES ('abcd');
SELECT * FROM t1 WHERE c1 LIKE '%cd';

The above SELECT won't return any rows. The reason is that CHAR columns are always padded with spaces to the full lenght, so column actually contains 'abcd ', with one space at the end. Take a look at FAQ #237 for more details.

To work around this, you should either use VARCHAR, or trim the column using either TRIM or RTRIM functions:

SELECT * FROM t1 WHERE RTRIM(c1) LIKE '%cd';

RTRIM function is a part of IB_UDF UDF library. If you don't have it declared, take a look at FAQ #169 to learn how to enable it.


Do you find this FAQ incorrect or incomplete? Please e-mail us what needs to be changed. To ensure quality, each change is checked by our editors (and often tested on live Firebird databases), before it enters the main FAQ database. If you desire so, the changes will be credited to your name. To learn more, visit our add content page.

If you are a commercial tool maker and your tool features a great way to handle the issue written about in this FAQ, please check out our advertisement page.



All contents are copyright © 2007-2017 FirebirdFAQ.org unless otherwise stated in the text.


Links   Firebird   News   FlameRobin   Home Inventory powered by FB  
Add content   Advertise   About  

Categories
 Newbies
 SQL
 Installation and setup
 Backup and restore
 Performance
 Security
 Connectivity and API
 HOWTOs
 Errors and error codes
 Miscellaneous