Rails: Update a column with the value of a column in another table

Asked Dec 20 '13 at 17:11

Active Mar 26 '19 at 04:26

Viewed 1,823 times

I have basically the following code:

ModelA.join(:modelB).update_all('modelA.column = modelB.column')

That fails with:

ActiveRecord::StatementInvalid: PG::UndefinedTable: ERROR:  missing FROM-clause entry for table "modelB"
LINE 1: ..." SET modelAs.column = modelBs...
                                                         ^
UPDATE "modelAs" SET modelAs.column = modelBs.column WHERE "modelAs"."id" IN (
  SELECT "modelAs"."id" FROM "modelAs" INNER JOIN "modelBs" ON "modelBs"."id" = "modelAs"."modelB_id"
)

Looking at the generated sql request, it is pretty obvious that Postgresql expects the modelB table to appear in the update part of the query. It there a way to do that or is it a bug?

(The issue is specific to Postgresql / the Postgresql rails adapter. The code above works fine with MySQL, the joins clause are also copied in the update part of the request)

asked Dec 20 '13 at 17:11

Such

2

Are you sure that this is supposed to work? I think you need to call select for the value. – phoet Dec 20 '13 at 20:09
I'm not sure that it's supposed to work. The documentation is not clear about it. But it works with MySQL! – Such Dec 21 '13 at 21:06
Selecting the value does not help. – Such Dec 26 '13 at 15:55
1

FYI: https://github.com/rails/rails/issues/13496 – Such Dec 22 '15 at 13:44

Rails: Update a column with the value of a column in another table

0 Answers0