feature proposal ...

hackers,

currently we have to hack tons of export scripts for various customers.
the problem is: if tables can be exported straight forward COPY will
give you all you need but when data has to be transformed while
exporting things start becoming a bit more complex. usually people want
to have CSV file (excel-ify data) which is supported by COPY.

the problem is: COPY can write data returned by a SELECT statement to a
file. our idea is to implement precisely that.

example:

COPY TO file_name USING some_select_statement;

the advantage would be that COPY would then be able to export data and
transform it on the fly. this would save many people a lot of work
because complex data extractors could in many cases be replaced by
simple SQL scripts.

how we plan to implement that:
currently copy simply opens a table and loops through the tuples (see
command/copy.c starting at line 1115).
to implement the desired feature we just had to add some SPI code to the
scenery (SPI will also return HeapTuples so it should fit in there).

Any comments?

Best regards,

Hans

--
Cybertec Geschwinde & Schönig GmbH
Schöngrabern 134; A-2020 Hollabrunn
Tel: +43/1/205 10 35 / 340
www.postgresql.at, www.cybertec.at