Insert into #temp_table from stored procedure with dynamic columns - sql

Question

I have a stored procedure which can return a variety of field names in its output. Something like this:
create or alter procedure dbo.my_prc (#return_format as int ) as
create table #all_data (id int ,chr varchar(10))
insert into #all_data
values (1,'a')
,(2,'b')
,(3,'c')
--return id -> id_2 only
if #return_format = 1
select id * 2 as 'id_2' from #all_data
--return chr -> chrq only
if #return_format = 2
select chr + '?' as 'chrq' from #all_data
--return everything
if #return_format = 3
select * from #all_data
Here are possible outputs:
exec my_prc #return_format = 1 --id_2
exec my_prc #return_format = 2 --chrq
exec my_prc #return_format = 3 --everything
How can I dynamically create a #temp_table (or a set of temp tables for 1-3) which will capture my field names and data?
This obviously doesn't work but something like this is what I'm thinking:
/*
exec my_prc #return_format = 1 into #temp_table
--or maybe
select top 0 from (exec my_prc #return_format = 1) into #temp_table --create a #temp_table with the field names
insert into #temp_table exec my_prc #return_format = 1
*/
For more context, I am trying to avoid simply declaring a static #temp_table and inserting into as such. I don't want to get into the weeds, but that is likely not a good option for me.
create table #temp_table (id int ,chr varchar(10))
insert into #temp_table
exec my_prc #return_format = 3

Answer 1

Here is a solution which writes to the database then creates a #temp_table from that newly created table
The stored procedure can look like this
create or alter procedure dbo.my_prc (#return_format as int ) as
create table #all_data (id int ,chr varchar(10))
insert into #all_data
values (1,'a')
,(2,'b')
,(3,'c')
drop table if exists dbo.output_table --drop so that you can reset the field names
--return id -> id_2 only
if #return_format = 1
select id * 2 as 'id_2' into dbo.output_table from #all_data
--return chr -> chrq only
if #return_format = 2
select chr + '?' as 'chrq' into dbo.output_table from #all_data
--return everything
if #return_format = 3
select * into dbo.output_table from #all_data
select * from dbo.output_table --if you still need to see the output in the SP
And then you can create your #temp_table off dbo.output_table
select * into #temp_table from dbo.output_table
Regardless of which value you choose for #return_format, dbo.output_table will have those fields

Answer 2

Have you tried to use Dynamic SQL?
It is a way to write your SQL in a string and then execute it.
e.g.
v_sql = "create table " + v_table_name + for loop with columns... ";
execute immediate v_sql;