Not support PostgreSQL

[DinaMagdalina]

The extension does not work with PostgreSQL.
Drops on this request:

SELECT COUNT (*)
FROM (
          SELECT MAX ("id") AS "last_message_id", IF ("sender_id" = 1, "receiver_id", "sender_id") AS "contact_id", 1 AS "user_id"
          FROM "simplechat_message" "c"
          WHERE ("receiver_id" = 1) AND ("is_deleted_by_receiver" = FALSE)) OR (("sender_id" = 1) AND ("is_deleted_by_sender" = FALSE)) GROUP BY "contact_id"
      ) "C"

Error:

SQLSTATE[42883]: Undefined function: 7 ERROR: function if(boolean, integer, integer) does not exist
LINE 1: ...T(*) FROM (SELECT MAX("id") AS "last_message_id", IF("sender...