Dear experts,
This point is confusing me with the || operator. I've got a table with
"one column per data type", like so:
# \d context_keyvals; Table "public.context_keyvals" Column | Type | Modifiers
-------------+-----------------------------+-----------context_key | integer | not nullkeyname
|text |t_number | integer |t_string | text
|t_boolean | boolean |t_date | timestamp without time zone |
Indexes: "context_keyvals_ck" btree (context_key) CLUSTER
Foreign-key constraints: "context_keyvals_context_key_fkey" FOREIGN KEY (context_key)
REFERENCES contexts(context_key) ON DELETE CASCADE
# select version()
PostgreSQL 8.3.8 on x86_64-pc-linux-gnu, compiled by GCC gcc-4.3.real
(Debian 4.3.2-1.1) 4.3.2
------------------------------
Just for pretty sake I'd like to be able to use psql to view it like this:
# select context_key,keyname,t_number||t_string||t_date||t_boolean as
value from context_keyvals;
But it is not working, the columns always come up empty. I can use the
|| operator to concatenate strings:
# select '--'||t_number::text from context_keyvals;
But the moment I try to combine columns, the result is blank.
# select '--'||t_number::text||t_string::text from context_keyvals;
What's up?