Here is how LIKE would be used: http://dev.mysql.com/doc/refman/5.7/en/pattern-matching.html
I assume your item_ID is some numeric type, right?
So you can use the =
operator:
If it realy is varchar (which I do not recommand for an identifier variable, because of performance issues), you would use:
SELECT * FROM coupons WHERE item_ID = '17';
If you want to find IDs containing the substring 17
then your query is allright.
If you have a commaseperated list of your IDs as string in that field (which I do not recommand) you should try this:
SELECT * FROM coupons WHERE item_ID LIKE '%,17,%' OR item_ID LIKE '%,17' OR item_ID LIKE '17,%' ;
check your content of that itme_ID
field. 117
, 1710
, ` etc. can be found with your query as well.