Date: Sat, 23 Oct 2021 06:09:25 -0700 (PDT)
From: TIM CHILD <tim.child@comcast.net>
To: SQL Padawan <sql_padawan@protonmail.com>,
	"pgsql-novice@lists.postgresql.org" <pgsql-novice@lists.postgresql.org>
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Subject: Re: Strange sequences - how to construct?
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Here is a way using multiple sequences:

drop sequence if exists controller_sequence;
drop sequence if exists odd_values;
drop sequence if exists even_values;
create sequence if not exists controller_sequence;
create sequence if not exists odd_values start with 1;
create sequence if not exists even_values start with 1;
create function next_my_sequence() returns integer as
$body$
declare
choose integer;
begin
choose = nextval('controller_sequence');
if choose % 2 equals then
return nextval('even_values');
else
return nextval('odd_values');
end if;
end;
$body$
language plpgsql;
-- example: get 5 sequences
select next_my_sequence(), next_my_sequence(), next_my_sequence(), next_my_sequence(), next_my_sequence();


>     On 10/22/2021 12:29 PM SQL Padawan <sql_padawan@protonmail.com> wrote:
> 
> 
> 
>     Good afternoon to everybody.
> 
>     I wish to construct some weird sequences.
> 
>     1
>     1
>     2
>     2
>     &c.
> 
>     and with  3 ones, 4 ones... &c.
> 
>     Now, I know how to do a simple
>     1
>     2
>     3
>     4
> 
>     using both GENERATE_SERIES and using a RECURSIVE CTE.
> 
>     What I would like is to be able to construct my specified sequences using *_both_* GENERATE_SERIES *_and_* RECURSIVE CTEs.
> 
>     Regards,
> 
>     SQL Padawan!
> 
> 
> 
> 
> 
>     Sent with ProtonMail https://protonmail.com/ Secure Email.
> 
> 

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<!doctype html>
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 <head> 
  <meta charset="UTF-8"> 
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 <body>
  <div style="font-size: 12pt; font-family: helvetica, arial, sans-serif; color: #333333;">
   Here is a way using multiple sequences:
  </div>
  <div style="font-size: 12pt; font-family: helvetica, arial, sans-serif; color: #333333;" class="default-style">
   <br>
  </div>
  <div style="font-size: 12pt; font-family: helvetica, arial, sans-serif; color: #333333;" class="default-style">
   <div class="default-style">
    drop sequence if exists controller_sequence;
    <br>drop sequence if exists odd_values;
    <br>drop sequence if exists even_values;
   </div>
   <div class="default-style">
    create sequence if not exists controller_sequence;
    <br>create sequence if not exists odd_values start with 1;
    <br>create sequence if not exists even_values start with 1;
   </div>
   <div class="default-style">
    create function next_my_sequence() returns integer as
    <br>$body$
    <br>declare 
    <br>choose integer;
    <br>begin
    <br>choose = nextval('controller_sequence');
    <br>if choose % 2 equals then
    <br>return nextval('even_values');
    <br>else 
    <br>return nextval('odd_values');
    <br>end if;
    <br>end;
    <br>$body$ 
    <br>language plpgsql;
   </div>
   <div class="default-style">
    -- example: get 5 sequences
    <br>select next_my_sequence(), next_my_sequence(), next_my_sequence(), next_my_sequence(), next_my_sequence();
    <br>
   </div>
   <div class="default-style" style="font-size: 12pt; font-family: helvetica, arial, sans-serif; color: rgb(51, 51, 51);">
    <br>
   </div>
   <div class="default-style" style="font-size: 12pt; font-family: helvetica, arial, sans-serif; color: rgb(51, 51, 51);">
    <br>
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  <blockquote type="cite">
   <div>
    On 10/22/2021 12:29 PM SQL Padawan &lt;sql_padawan@protonmail.com&gt; wrote:
   </div>
   <div>
    <br>
   </div>
   <div>
    <br>
   </div>
   <div>
    <br>
   </div>
   <div>
    Good afternoon to everybody.
    <br>
   </div>
   <div>
    <br>
   </div>
   <div>
    I wish to construct some weird sequences.
   </div>
   <div>
    <br>
   </div>
   <div>
    1
    <br>
   </div>
   <div>
    1
    <br>
   </div>
   <div>
    2
    <br>
   </div>
   <div>
    2
    <br>
   </div>
   <div>
    &amp;c.
    <br>
   </div>
   <div>
    <br>
   </div>
   <div>
    and with&nbsp; 3 ones, 4 ones... &amp;c.
    <br>
   </div>
   <div>
    <br>
   </div>
   <div>
    Now, I know how to do a simple
    <br>
   </div>
   <div>
    1
    <br>
   </div>
   <div>
    2
    <br>
   </div>
   <div>
    3
    <br>
   </div>
   <div>
    4
    <br>
   </div>
   <div>
    <br>
   </div>
   <div>
    using both GENERATE_SERIES and using a RECURSIVE CTE.
    <br>
   </div>
   <div>
    <br>
   </div>
   <div>
    What I would like is to be able to construct my specified sequences using *_both_* GENERATE_SERIES *_and_* RECURSIVE CTEs.
    <br>
   </div>
   <div>
    <br>
   </div>
   <div>
    Regards,
    <br>
   </div>
   <div>
    <br>
   </div>
   <div>
    SQL Padawan!
    <br>
   </div>
   <div>
    <br>
   </div>
   <div>
    <br>
   </div>
   <div>
    <br>
   </div>
   <div>
    <br>
   </div>
   <div class="protonmail_signature_block">
    <div class="protonmail_signature_block-user protonmail_signature_block-empty">
     <br>
    </div>
    <div class="protonmail_signature_block-proton">
     Sent with <a target="_blank" href="https://protonmail.com/" rel="noopener">ProtonMail</a> Secure Email.
    </div>
   </div>
   <div>
    <br>
   </div>
  </blockquote>
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