can we declare variable dynamically

Question

Question 1: with in store procedure,can we declare variable dynamically like below:

declare @i int =1;
declare @s nvarchar(max) ='';
while(@i<5)  
begin 
set @s = concat('declare @temp',@i,' nvarchar(max);');
exec (@s);
set @i=@i + 1;
end

if we can declare the variable dynamically like above then what will be the scope of this kind of variable? with in that store procedure?

Question 2: we do not need to declare session variable in mysql so can we have same kind of session variable in sql server.

Actually I am converting mysql script to sql server script and I am finding difficulties with variable declaration because in mysql I have used session variables.

Thanks in advance..

Answer 1

Yes, and no

You can declare the variable dynamically, and exec the command, but its scope will be within that exec statement, so it will vanish afterwards.

You can do

declare @t nvarchar(100) = 'declare @v int; select @v = 1; select @v+1'
exec (@t)

Or you can pass variables to commands with sp_executesql.