try to cast to "xml".... xml_payload::xml El mié, 10-02-2010 a las 12:39 +0300, Allan Kamau escribió: > As advised by Peter, > Below is an example (including the ddl and dml statements), it _drops_ > and creates a table called "simple_table" and a sequence called > "simple_table_seq" both in the "public" schema. > > DROP SEQUENCE IF EXISTS simple_table_seq CASCADE; > CREATE SEQUENCE simple_table_seq; > DROP TABLE IF EXISTS simple_table CASCADE; > CREATE TABLE simple_table > (id INTEGER NOT NULL DEFAULT NEXTVAL('simple_table_seq') > ,xml_payload TEXT > ,PRIMARY KEY(id) > ) > ; > INSERT INTO simple_table > ( > id > ,xml_payload > ) > SELECT > nextval('simple_table_seq')AS id > ,'<doc><name first="David" last="Marston"/>some text</doc>' AS xml_payload > ; > SELECT a.id,a.xml_payload FROM simple_table a LIMIT 1; > SELECT xpath('/doc/name/@first',SELECT a.xml_payload FROM simple_table > a LIMIT 1); > SELECT a.id,xpath('/doc/name/@first',a.xml_payload) FROM simple_table a LIMIT 1; > > SELECT xpath('/doc/name/@first','<doc><name first="David" > last="Marston"/>some text</doc>'); > > DROP SEQUENCE IF EXISTS simple_table_seq CASCADE; > DROP TABLE IF EXISTS simple_table CASCADE; > > > Allan. > > On Wed, Feb 10, 2010 at 11:34 AM, Otandeka Simon Peter > <sotandeka@xxxxxxxxx> wrote: > > Allan, > > > > Postgres is very strict on variable types and char conversion. I have a > > feeling you are trying to access data from a varchar feild using an > > integer... > > > > Can you paste here your schema for that table? > > > > P. > > > > On Wed, Feb 10, 2010 at 11:06 AM, Allan Kamau <kamauallan@xxxxxxxxx> wrote: > >> > >> Hi, > >> I am running postgreSQL-8.4.2. I have a table that stores a single xml > >> document per row in one of it's fields. I would like to use xpath to > >> retrieve portions of these xml documents. > >> Is there a way to do so. (I am running postgreSQL 8.4.2 configured > >> (built) with --with-libxml and --with-libxslt options) > >> > >> I have looked at 'xpath' but I am unable to get it work for table fields. > >> > >> The command below works. > >> SELECT xpath('/doc/name/@first','<doc><name first="David" > >> last="Marston"/>...</doc>'); > >> > >> The command below seems not to execute successfully > >> SELECT a.id,xpath('/doc/name/@first',a.xml_payload) FROM > >> staging.simple_table a WHERE a.id=1; > >> > >> HINT: No function matches the given name and argument types. You > >> might need to add explicit type casts. > >> > >> > >> Allan. > >> > >> -- > >> Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) > >> To make changes to your subscription: > >> http://www.postgresql.org/mailpref/pgsql-general > > > > > -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general