add coalesce for GettingAmoUsersTrueResults

dal/db_query/queries.sql

@@ -971,10 +971,10 @@ VALUES ($1, $2, $3, $4, $5, $6);
 
 -- name: GettingAmoUsersTrueResults :many
 SELECT a.quiz_id,a.id,a.result,a.question_id,a.content,a.session,
-      (SELECT a2.utm
+      COALESCE((SELECT a2.utm
       FROM answer a2
       WHERE a2.start = true AND a2.session = a.session
-      LIMIT 1) AS utm
+      LIMIT 1), '{}') AS utm
 ,t.accesstoken,r.accountid,r.fieldsrule,r.tagstoadd,r.performerid,r.stepid,r.pipelineid,(SELECT u.name FROM usersAmo u WHERE u.AmoUserID = r.performerid AND u.deleted = false) AS performer_name,u.subdomain,u.accountid,u.driveurl
 FROM answer a
          INNER JOIN quiz q ON a.quiz_id = q.id