Query CRM database using deluge with "contains" condition - COQL API query

I am trying to find a way to query the database with a "contains" not "equals" (which can be done using zoho.crm.searchRecords) but I think a field can be searched based on "contains" using COQL Api Query. This is what I am working on but I don't have it yet:

contactId = 5122008000000796037;

contactMap = Map();

contactId = zoho.crm.getRecordById("Contacts",contactId);

mailCode = contactId.get("Legacy_Mail_Code");

info contactId;

info mailCode;

queryMap = Map();

queryMap.put = ("select_query", "select * from Campaigns where Mail_Code like '" + mailCode + "'");

campaignMap = Map();

campaignMap = invokeurl

[

url :"https://www.zohoapis.com/crm/v3/coql"

type :POST

parameters:queryMap.toString()

connection:"zohocrm"

];

info campaignMap;

I get "Syntax error. Expecting ')'. Found ','.
Line Number: 8" which is the queryMap.put line