Re: Re: Support plpgsql multi-range in conditional control

On Wed, 25 Jan 2023 at 12:02, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> wrote:

>
>
> st 25. 1. 2023 v 17:22 odesílatel songjinzhou <2903807914(at)qq(dot)com> napsal:
>
>>
>> As follows, we can only repeat the for statement before we use such SQL:
>>
>> begin
>> for i in 10..20 loop
>> raise notice '%', i; -- Things to do
>> end loop;
>>
>> for i in 100 .. 200 by 10 loop
>> raise notice '%', i; -- Things to do
>> end loop;
>> end;
>>
>> But now we can simplify it as follows:
>>
>> begin
>> for i in 10..20, 100 .. 200 by 10 loop
>> raise notice '%', i; -- Things to do
>> end loop;
>> end;
>>
>> Although we can only use integer iterative control here, this is just a
>> horizontal expansion of the previous logic. Thank you very much for your
>> reply. I am very grateful!
>>
>>
> Unfortunately, this is not a real use case - this is not an example from
> the real world.
>

And anyway, this is already supported using generate_series() and UNION:

odyssey=> do $$ declare i int; begin for i in select generate_series (10,
20) union all select generate_series (100, 200, 10) do loop raise notice
'i=%', i; end loop; end;$$;
NOTICE: i=10
NOTICE: i=11
NOTICE: i=12
NOTICE: i=13
NOTICE: i=14
NOTICE: i=15
NOTICE: i=16
NOTICE: i=17
NOTICE: i=18
NOTICE: i=19
NOTICE: i=20
NOTICE: i=100
NOTICE: i=110
NOTICE: i=120
NOTICE: i=130
NOTICE: i=140
NOTICE: i=150
NOTICE: i=160
NOTICE: i=170
NOTICE: i=180
NOTICE: i=190
NOTICE: i=200
DO
odyssey=>

The existing x..y notation is just syntactic sugar for a presumably common
case (although I’m dubious how often one really loops through a range of
numbers — surely in a database looping through a query result is
overwhelmingly dominant?); I don’t think you’ll find much support around
here for adding more syntax possibilities to the loop construct.