[GENERAL] combining semi-duplicate rows
Hello, I have a table of rows which partially duplicate one another and need to be merged and moved into a table with a primary key. As an additional complication, some of the duplicates contain different information, ex.: schema1.datatable: key1 None None 34 schema2.datatable: key1 127None desired result: schema1.datatable: key1 1234 I looked for a specific function that would do this sort of merge and failed. So I tried: UPDATE schema1.datatable SET schema1.datatable.field1 = schema2.datatable.field1 FROM schema2.datatable WHERE schema2.datatable.keyfield = schema1.datatable.keyfield AND schema1.datatable.field1 = None; Which is suboptimal because I'd need a command for each field, but it would be a start. However, the schema names are not recognised. I get error messages to the effect that cross-database references are not implemented or relation schema1/2 does not exist.Even the much simpler SELECT DISTINCT schema2.datatable INTO schema1.datatable; ...gives me these messages. Qualifying right up to the database level produces improper qualified name (too many dotted names). I'm pretty sure that this isn't a capitalization/quoting problem as described in the FAQ. Is it not possible to use these functions between schemas? Or am I misusing the functions in a more basic way? The problem is somewhat similar to this one: http://archives.postgresql.org/pgsql-sql/2007-02/msg00055.php Namely, Regards, H.Jenkins ---(end of broadcast)--- TIP 5: don't forget to increase your free space map settings
Re: [GENERAL] combining semi-duplicate rows
hjenkins [EMAIL PROTECTED] writes: So I tried: UPDATE schema1.datatable SET schema1.datatable.field1 = schema2.datatable.field1 FROM schema2.datatable WHERE schema2.datatable.keyfield = schema1.datatable.keyfield AND schema1.datatable.field1 = None; Which is suboptimal because I'd need a command for each field, but it would be a start. However, the schema names are not recognised. I get error messages to the effect that cross-database references are not implemented or relation schema1/2 does not exist. The target column of a SET clause can't be qualified with the relation name; it would introduce ambiguity in the case of composite-type fields, and it's useless anyway since the target relation was already given. Your example works for me (syntactically at least) as regression=# UPDATE schema1.datatable SET field1 = schema2.datatable.field1 FROM schema2.datatable WHERE schema2.datatable.keyfield = schema1.datatable.keyfield AND schema1.datatable.field1 = 'None'; UPDATE 0 Personally, though, I'd use some aliases to improve readability and forestall the onset of carpal tunnel syndrome: regression=# UPDATE schema1.datatable t SET field1 = s.field1 FROM schema2.datatable s WHERE s.keyfield = t.keyfield AND t.field1 = 'None'; UPDATE 0 regards, tom lane ---(end of broadcast)--- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
