Plpgsql - Custom fields Postgres 9.5

[Patrick B <patrickbakerbr@xxxxxxxxx>]

Hi,

I've got this query, that I manually run it once a month:

SELECT

    uuid,

    clientid),

    *

FROM

    logging

WHERE

    logtime

BETWEEN

    '201611015'

AND

    '201612015'

As you can see, I select a date. So in December, the date will be: BETWEEN '201612015' AND '201601015', for example.

I always need to run this on the 15th of each month.

I was thinking about creating a PLPGSQL function and a Cron task, so this task can be automated.

Also, the file must be saved with the date+.csv. Example:

CREATE or REPLACE FUNCTION logextract(date_start integer, date_end integer)

    RETURNS void AS $$

    begin

      execute '

      COPY 

          (

          SELECT

              uuid,

              clientid),

              *

          FROM

              logging

          WHERE

              logtime

          BETWEEN

             ' || date_start || '

          AND

              ' || date_end || '

          )

      TO ''/var/lib/postgresql/'|| date_start ||'_logs.csv''';

    end

    $$ language 'plpgsql';

Questions:

1. Why when I run the function manually I get this error?

select logextract(201612015, 201612015);

ERROR:  operator does not exist: timestamp without time zone >= integer

LINE 13:                 BETWEEN

 I presume this is wrong: CREATE or REPLACE FUNCTION logextract(date_start integer, date_end integer) - But what should I use instead?

2. To call the function, I have to login to postgres and then run: select logextract(201612015, 201612015);
How can I do it on cron? because the dates will be different every time.

Thanks

Patrick