Thread: inconsistent functionality with LIKE operator

I'm using PostgreSQL version 7.1, and I'm having trouble with the LIKE
statement.  How would I find the value "a\bc"?  I tried using the
backslash to escape it: LIKE 'a\\b%';

If I specify: LIKE 'a\\bc', then it works, but if I wanted it to look
for consecetive characters after the c, using the %, then it returns
other values besides what I'm looking for.

I also have the same problem with percent (%).  I have a test string
with the value "ab%c", and I want to look for that using LIKE.  I tried:
LIKE 'ab\%c', LIKE 'ab%%', and LIKE 'ab\%_', but these statements not
only returned what I was looking for, but also other values:
"abc","ABC", and "Abc".

Phuong

Phuong Ma <pma@commandprompt.com> writes:
> I'm using PostgreSQL version 7.1, and I'm having trouble with the LIKE
> statement.  How would I find the value "a\bc"?  I tried using the
> backslash to escape it: LIKE 'a\\b%';

I think you need four backslashes.  The string-literal parser eats one
level of backslashes, but you need the pattern that arrives at LIKE
to look like "a\\b%".

BTW, "PostgreSQL version 7.1" does not exist yet.

            regards, tom lane

On Thu, Mar 29, 2001 at 08:25:30AM +0000, Phuong Ma wrote:
> I'm using PostgreSQL version 7.1, and I'm having trouble with the LIKE
> statement.  How would I find the value "a\bc"?  I tried using the
> backslash to escape it: LIKE 'a\\b%';
>
> If I specify: LIKE 'a\\bc', then it works, but if I wanted it to look
> for consecetive characters after the c, using the %, then it returns
> other values besides what I'm looking for.
>
> I also have the same problem with percent (%).  I have a test string
> with the value "ab%c", and I want to look for that using LIKE.  I tried:
> LIKE 'ab\%c', LIKE 'ab%%', and LIKE 'ab\%_', but these statements not
> only returned what I was looking for, but also other values:
> "abc","ABC", and "Abc".

with LIKE, '%' means "anything" just as /.*/ does in a perl
regex; and '_' means "any character" just as /./ does in perl.

by default.

you can change the escape char, tho --

http://google.com/search?as_q=like+select+escape&as_sitesearch=postgresql.org


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