Question

I have a table “queued_items”. The current “user_id” and “item_id” are incorrect, but are stored in the other tables: users.imported_id and items.imported_id

Trying to grab the imported_id from the other tables and update. Here’s what I tried

UPDATE queued_items
SET queued_items.user_id = users.id,
    queued_items.item_id = items.id
FROM queued_items
INNER JOIN users ON queued_items.user_id = users.imported_id
INNER JOIN items ON queued_items.item_id = items.imported_id

Getting this error:

Error : ERROR:  table name "queued_items" specified more than once

Tried removing the FROM line, got this error:

Error : ERROR:  syntax error at or near "INNER"
LINE 4: INNER JOIN users ON queued_items.user_id = users.imported_id
         ^

I also tried adding an alias to the FROM and JOIN conditions

UPDATE queued_items
SET queued_items.user_id = users.id,
    queued_items.item_id = items.id
FROM queued_items as qi
INNER JOIN users ON qi.user_id = users.imported_id
INNER JOIN items ON qi.item_id = items.imported_id

Got this error:

Error : ERROR:  column "queued_items" of relation "queued_items" does not exist
LINE 2: SET queued_items.user_id = users.id,
            ^

Any ideas? (postgres 9)

PS Trying to avoid this sub-query:

UPDATE queued_items
SET user_id = (SELECT id FROM users WHERE queued_items.user_id = users.imported_id),
    item_id = (SELECT id FROM items WHERE queued_items.item_id = items.imported_id)

…because it’s crazy slow

Answer 1

Try this:

UPDATE queued_items
SET user_id = users.id,
    item_id = items.id
FROM users, items
WHERE queued_items.user_id = users.imported_id
  AND queued_items.item_id = items.imported_id

Yeah, old school join conditions.