Not able to run block in PostgreSQL 8.2 - postgresql

Question

I can't run this block in PostgreSQL 8.2.
DECLARE
curtime char;
BEGIN
curtime := 'now';
INSERT INTO logtable VALUES (logtxt, curtime);
RETURN curtime;
END;
When I try it shows the error:
ERROR: syntax error at or near "char"
SQL state: 42601

Answer 1

It sounds like you're trying to run a PL/PgSQL code block stand-alone, without wrapping it up in a function using CREATE OR REPLACE FUNCTION. That won't work, you need to include it in a function or (from PostgreSQL 9.0) a DO block. PL/PgSQL and plain SQL are different languages so you can't just run PL/PgSQL code directly.
It'd help if you explained why you're trying to write the code you pasted. I suspect you're trying to solve a problem that's better handled with a trigger function like an audit trigger.
Some important notes:
You need to update PostgreSQL: PostgreSQL 8.2 is dangerously out of date and unsupported. security and bug fixes are no longer being released. Upgrade urgently to a supported version, but make sure to read the release notes for each major ".0" version like "8.3.0", "8.4.0", etc for migration and compatibility advice.
Avoid 'now': Also, instead of using 'now' you should usually use the current date/time functions, particularly current_timestamp.
current_timestamp is stable: The hoop-jumping you are doing is probably unnecessary because the value of current_timestamp (and 'now'::timestamp) doesn't change for the duration of a transaction. Eg:
regress=# BEGIN;
regress=# SELECT current_timestamp;
2012-08-14 14:52:43.382596+08
regress=# SELECT pg_sleep(5);
regress=# SELECT current_timestamp;
2012-08-14 14:52:43.382596+08
Details
Your intention appears to be something like the following (incorrect, do not use) code:
CREATE OR REPLACE FUNCTION some_function(logtxt text) RETURNS timestamptz AS $$
DECLARE
curtime char;
BEGIN
curtime := 'now';
INSERT INTO logtable VALUES (logtxt, curtime);
RETURN curtime;
END;
$$ LANGUAGE 'plpgsql';
but you've misused the char datatype, which requires a length parameter. It defaults to 1 if not supplied so you'll get:
regress=# SELECT some_function();
ERROR: value too long for type character(1)
CONTEXT: PL/pgSQL function "some_function" line 5 at assignment
NEVER use the char datatype in SQL; use varchar or text. For cross-database portability varchar(n) where n is a maximum length is required; if portability isn't needed use text.
If you change char to text in the above, your code might run, but it still doesn't make any sense. I strongly suspect that you really want to write:
CREATE OR REPLACE FUNCTION some_function(logtxt text) RETURNS timestamptz AS $$
BEGIN
INSERT INTO logtable VALUES (logtxt, current_timestamp);
RETURN current_timestamp;
END;
$$ LANGUAGE 'plpgsql';
... but you didn't know about the current date/time functions.
Even that's too much, really. I think you're trying to solve a problem that's a better fit for a trigger.