Postal Code Search And LIKE Statement

I'm trying to create a form that allows someone to find an
address from a postal code search in the database. My query works exactly as I’d
like in query builder using the following select:



Select [FIELD_LIST] from addresses WHETE POSTCODE LIKE ‘%’+@POSTCODE+’%’





I then pass the user entered post code to the select statement
which is executed. However, I’m getting some odd behaviour. Assuming there is
an address in the database with the post code
 
“LS11 0ES”...
 

If I search for LS11, nothing is returned;

If I search for LS11%, nothing is returned;

If I search for %LS11%, nothing is returned;

If I search for %LS11%%, the data is returned.

If I search for %LS%1%%, the data is returned (as is LS21
0ES etc. etc.).

 

However, I want the user to be able to enter shorter search
strings and it to pull all the data back out, so they can enter a substring
such as LS and it will pull out all the data without the users needing to enter
the full pattern of % symbols.



If I go into query builder (in visual web developer) and
enter just “LS” it works as I’d want, but not when pulled from a web page.



Any ideas?



Thanks