PostgreSQL support

[le0pard]

Hello. Looks like this gem will not work in PostgreSQL, only MySQL (no support for ORDER BY FIELD()). You can use something like this for PostgreSQL:

SELECT foo.* FROM foo                                           
JOIN (SELECT id.val, row_number() over() FROM (VALUES(3),(2),(6),(1),(4)) AS
id(val)) AS id
ON (foo.catalog_id = id.val) ORDER BY row_number;

example:

$ SELECT * FROM users WHERE id IN (3,2,1) ORDER BY FIELD(id, 3,2,1);
ERROR:  function field(integer, integer, integer, integer) does not exist
LINE 1: SELECT * FROM users WHERE id IN (3,2,1) ORDER BY FIELD(id, 3...
                                                         ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.

$ SELECT users.* FROM users JOIN (SELECT id.val, row_number() over() FROM (VALUES(3),(2),(1)) AS id(val)) AS id ON (users.id = id.val) ORDER BY row_number;

id |      name
----+-----------------
  2 |
  1 | Alexey Vasiliev
(2 rows)

[khiav223577]

Thanks for the hint :)
I'll take a look at it soon.
Or would you mind submitting a PR?

[le0pard]

@khiav223577 sorry, don't have time right now :(

[khiav223577]

It's OK. Thanks for your hint again :)

[khiav223577]

Just submitted a PR for this. - #7

[khiav223577]

1.1.0 was released. It supports PostgreSQL now.

[darcang]

@khiav223577 Hey, is there any solution to support pgsql uuid type?

[khiav223577]

@darcang
What is your error message of using uuid type?
operator does not exist: uuid = text?

[darcang]

@khiav223577 yeah, i got this working for PG >= 9.5 using

User.where(id: ids)
  .order(Arel.sql("array_position(ARRAY['#{ids.join("','")}']::uuid[], users.id)"))

[khiav223577]

Hi, @darcang
I released 1.3.0 to support psql uuid type.
See the implementation here: #18

[darcang]

@khiav223577 nice, great thx!