This happens when I search for a specific host in the dashboard search. The 'Run distribution chart' widget then errors out with message:

ActionView::Template::Error: PG::DuplicateAlias: ERROR:  table name "reports" specified more than once

The Foreman log shows the exact SQL query which looks like this (prettied up):

SELECT COUNT(DISTINCT "hosts"."id") FROM "hosts" 
LEFT OUTER JOIN "reports" ON "reports"."host_id" = "hosts"."id" AND "reports"."type" IN ('ConfigReport')
LEFT OUTER JOIN "models" ON "models"."id" = "hosts"."model_id" 
LEFT OUTER JOIN "hostgroups" ON "hostgroups"."id" = "hosts"."hostgroup_id" 
LEFT OUTER JOIN "nics" ON "nics"."host_id" = "hosts"."id" AND "nics"."primary" = $1
LEFT OUTER JOIN "domains" ON "domains"."id" = "nics"."domain_id" 
LEFT OUTER JOIN "realms" ON "realms"."id" = "hosts"."realm_id" 
LEFT OUTER JOIN "environments" ON "environments"."id" = "hosts"."environment_id" 
LEFT OUTER JOIN "architectures" ON "architectures"."id" = "hosts"."architecture_id" 
LEFT OUTER JOIN "compute_resources" ON "compute_resources"."id" = "hosts"."compute_resource_id" 
LEFT OUTER JOIN "images" ON "images"."id" = "hosts"."image_id" 
LEFT OUTER JOIN "operatingsystems" ON "operatingsystems"."id" = "hosts"."operatingsystem_id" 
LEFT OUTER JOIN "nics" "primary_interfaces_hosts" ON "primary_interfaces_hosts"."host_id" = "hosts"."id" AND "primary_interfaces_hosts"."primary" = $2
LEFT OUTER JOIN "nics" "primary_interfaces_hosts_join" ON "primary_interfaces_hosts_join"."host_id" = "hosts"."id" AND "primary_interfaces_hosts_join"."primary" = $3
LEFT OUTER JOIN "subnets" ON "subnets"."id" = "primary_interfaces_hosts_join"."subnet_id" AND "subnets"."type" = $4
LEFT OUTER JOIN "nics" "primary_interfaces_hosts_join_2" ON "primary_interfaces_hosts_join_2"."host_id" = "hosts"."id" AND "primary_interfaces_hosts_join_2"."primary" = $5
LEFT OUTER JOIN "subnets" "subnet6s_hosts" ON "subnet6s_hosts"."id" = "primary_interfaces_hosts_join_2"."subnet6_id" AND "subnet6s_hosts"."type" = $6
LEFT OUTER JOIN "nics" "provision_interfaces_hosts" ON "provision_interfaces_hosts"."host_id" = "hosts"."id" AND "provision_interfaces_hosts"."provision" = $7
INNER JOIN reports ON reports.host_id = hosts.id 
WHERE "hosts"."type" IN ('Host::Managed') AND (("hosts"."name" ILIKE '%lxserv940%' OR "hosts"."comment" ILIKE '%lxserv940%' OR "reports".  "origin" ILIKE '%lxserv940%'  OR "models"."name" ILIKE '%lxserv940%' OR "hostgroups"."name" ILIKE '%lxserv940%' OR "hostgroups"."title" ILIKE '%lxserv940%' OR "domains". "name" ILIKE '%lxserv940%'   OR "realms"."name" ILIKE '%lxserv940%' OR "environments"."name" ILIKE '%lxserv940%' OR "architectures"."name" ILIKE '%lxserv940%' OR          "compute_resources"."name" ILIKE '%lxserv940%' OR "images"."name" ILIKE '%lxserv940%' OR "operatingsystems"."name" ILIKE '%lxserv940%' OR "operatingsystems".            "description" ILIKE        '%lxserv940%' OR "operatingsystems"."title" ILIKE '%lxserv940%' OR "nics"."ip" ILIKE '%lxserv940%' OR "subnets"."network" ILIKE '%lxserv940%' OR     "subnets"."name"    ILIKE '%lxserv940%' OR "subnets"."network" ILIKE '%lxserv940%' OR "subnets"."name" ILIKE '%lxserv940%' OR "hosts"."uuid" ILIKE '%lxserv940%' OR "nics". "mac" ILIKE      '%lxserv940%')) AND "reports"."origin" = $8 AND (reports.reported_at BETWEEN '2018-08-22 09:42:20.568842' AND '2018-08-22 09:49:20.568842')

The problem is that there is both a 'LEFT OUTER JOIN' and an 'INNER JOIN' on the reports table, which seem to conflict. Maybe the INNER JOIN can be removed, or the joins on the report table should be aliased?

This is on Foreman 1.18.0.