Steps to reproduce the issue

Pull latest changes from the 4.0-dev branch so you have the latest corrections of joomla.sql for PostgreSQL from today's merged PR's and do the composer install and npm install stuff in case if there have been other changes meanwhile which require this.

Then do an installation using a PostgreSQL database.

Result: Installation finishs with success.

Login to the administrator backend.

Expected result

The control panel does not show SQL errors.

Actual result

The control panel shows an SQL error:

In the log file of PostgreSQL (if logging is switched on):
2018-08-28 16:52:53.963 CEST [108726] jdb2adm@joomladb2 ERROR: invalid input syntax for integer: "f" 2018-08-28 16:52:53.963 CEST [108726] jdb2adm@joomladb2 STATEMENT: INSERT INTO "j4ux0_session" ("session_id","guest","time","userid","username","client_id") VALUES ($1, $2, $3, $4, $5, $6) 2018-08-28 16:52:54.030 CEST [108727] jdb2adm@joomladb2 ERROR: syntax error at or near "WHERE" at character 937 2018-08-28 16:52:54.030 CEST [108727] jdb2adm@joomladb2 STATEMENT: SELECT a.id, a.title, a.checked_out, a.checked_out_time, a.publish_up, a.hits,l.title AS language_title, l.image AS language_image,uc.name AS editor,ag.title AS access_level,c.title AS category_title,ua.name AS author_name,"wa"."stage_id" AS "stage_id","ws"."title" AS "stage_title","ws"."condition" AS "stage_condition","ws"."workflow_id" AS "workflow_id",COALESCE(NULLIF(ROUND(v.rating_sum / v.rating_count, 0), 0), 0) AS rating, COALESCE(NULLIF(v.rating_count, 0), 0) as rating_count FROM j4ux0_content AS a LEFT JOIN "j4ux0_languages" AS l ON l.lang_code = a.language LEFT JOIN j4ux0_users AS uc ON uc.id=a.checked_out LEFT JOIN j4ux0_viewlevels AS ag ON ag.id = a.access LEFT JOIN j4ux0_categories AS c ON c.id = a.catid LEFT JOIN j4ux0_users AS ua ON ua.id = a.created_by INNER JOIN "j4ux0_workflow_associations" AS "wa" INNER JOIN "j4ux0_workflow_stages" AS "ws" LEFT JOIN j4ux0_content_rating AS v ON a.id = v.content_id WHERE "wa"."item_id" = "a"."id" AND "ws"."id" = "wa"."stage_id" AND "ws"."condition" IN (1, 0) AND "wa"."extension"='com_content' ORDER BY a.hits DESC LIMIT 5

System information (as much as possible)

PHP 7.2
postgresql 10.5 (Ubuntu 10.5-0ubuntu0.18.04)

Additional comments

There could be 2 errors as far as I can see in the postgresql log file: One related to insert into the session table, and the other one related to workflow stuff.