Re: postgres sql assistance

On 1/16/24 6:34 AM, arun chirappurath wrote:
> I am trying to load data from the temp table to the main table and catch
> the exceptions inside another table.

I don't have a specific answer, but do have a few comments:

- There are much easier ways to do this kind of data load. Search for
"postgres data loader" on google.

- When you're building your dynamic SQL you almost certainly should have
some kind of ORDER BY on the queries pulling data from
information_schema. SQL never mandates data ordering except when you
specifically use ORDER BY, so the fact that your fields are lining up
right now is pure luck.

- EXCEPTION WHEN others is kinda dangerous, because it traps *all*
errors. It's much safer to find the exact error code. An easy way to do
that in psql is \errverbose [1]. In this particular case that might not
work well since there's a bunch of different errors you could get that
are directly related to a bad row of data. BUT, there's also a bunch of
errors you could get that have nothing whatsoever to do with the data
you're trying to load (like if there's a bug in your code that's
building the INSERT statement).

- You should look at the other details you can get via GET STACKED
DIAGNOSTICS [2]. As far as I can tell, your script as-written will
always return the first column in the target table. Instead you should
use COLUMN_NAME. Note that not every error will set that though.

1:
https://www.postgresql.org/docs/current/app-psql.html#APP-PSQL-META-COMMAND-ERRVERBOSE
2:
https://www.postgresql.org/docs/current/plpgsql-control-structures.html#PLPGSQL-EXCEPTION-DIAGNOSTICS
--
Jim Nasby, Data Architect, Austin TX