Mysql find_in_set with Join not working in postgres

Question

My mysql query is working proper in SQL database server but when i run same query in Postgres database than find set is not working. below is my query :

SELECT omh.id as idd, omh.modified as modified, omh.modified as modified1, 
DATE_FORMAT(omh.modified, '%m/%d/%Y') as only_date, DATE_FORMAT(omh.modified, '%h:%i %p') as only_time

FROM order_memo_history as omh

LEFT JOIN users as usr ON (FIND_IN_SET(usr.user_id, omh.users_id) != 0)

INNER JOIN service_order as so ON omh.order_id = so.o_id
LEFT JOIN users as u ON omh.user_id = u.user_id
WHERE (omh.modified BETWEEN "2017-09-01 06:00:00" AND "2017-10-27 05:59:00")
AND IF((so.merge_company_id='0'),(omh.company_id = 2819), ((omh.order_id = so.o_id AND omh.company_id = so.merge_company_id) OR (so.merge_company_id = 2819 
        AND (omh.group_id = 2819 OR omh.group_id = '0'))))
GROUP BY idd ORDER BY modified ASC

I am getting error

ERROR:  function find_in_set(integer, text) does not exist
LINE 6: LEFT JOIN users as usr ON (FIND_IN_SET(usr.user_id, omh.user...

I have try with string_to_array but not worked

Answer 1

Postgresql Solution :
Use of functions string_to_array and any can help you in getting the desired result.

Following example can give you some understanding on how to apply the function.

In the example below, assume that the string '2,4,11,5,8,6' is comma separated user ids from the field omh.users_id and values 11 , 1 , 9 are user ids from the field usr.user_id .

select string_to_array( '2,4,11,5,8,6', ',' ) as sa
     , '11' = any( string_to_array( '2,4,11,5,8,6', ',' ) ) as matched
     , '1' = any( string_to_array( '2,4,11,5,8,6', ',' ) ) as un_matched_1
     , '9' = any( string_to_array( '2,4,11,5,8,6', ',' ) ) as un_matched_2

Result would be like this:

+----------------+---------+--------------+--------------+
| sa             | matched | un_matched_1 | un_matched_2 |
| text[]         | boolean | boolean      | boolean      |
+----------------+---------+--------------+--------------+
| {2,4,11,5,8,6} | t       | f            | f            |
+----------------+---------+--------------+--------------+