I have a table:
kr=# create table t (u uuid[]);
CREATE TABLE
Time: 3.742 ms
kr=# insert into t values ('{"0289b709-3cd7-431c-bcbe-f942eb31b4c5","86cc14d6-7293-488e-a85f-384ae6773d28"}');
INSERT 0 1
Time: 1.735 ms
I recently did the following:
kr=# alter table t alter u type text[];
ALTER TABLE
Time: 5.513 ms
Now I'd like to put it back the way it was, but my attempts didn't work:
kr=# alter table t alter u type uuid[];
ERROR: column "u" cannot be cast automatically to type uuid[]
HINT: Specify a USING expression to perform the conversion.
Time: 0.244 ms
kr=# alter table t alter u type uuid[] using array(select unnest(u));
ERROR: cannot use subquery in transform expression
Time: 0.299 ms
I noticed that when I inserted a record into the table, postgres was able to convert my input string to uuid[] with no problem, so I tried simulating that, but to no avail:
kr=# alter table t alter u type uuid[] using array_to_string(u,',');
ERROR: column "u" cannot be cast automatically to type uuid[]
HINT: Specify a USING expression to perform the conversion.
Time: 0.321 ms
(Interestingly, postgres seems to think I don't even have a USING clause here. Could there be some optimization that removed it?)
I'm not sure what to do here. Can someone help me?