Problem facing with SQL Query, ORA-01425: escape character must be character string of length 1

select product_id from in_prod_qry_gtv where full_desc
like '%' || 'ALEX\\%DIAMOND\\%' || '%' escape '\\'

solutio i got when i googled is that "Change it to a character string of length 1."
but , still it is not resolving my problem.