if object_id('tempdb.dbo.#tmp') is not null drop table #tmp;

create table #tmp (id int);

declare @sql varchar(2000);
set @sql = 'insert into #tmp(id) values (1);';
exec (@sql);

select * from #tmp;

id
-----------
1

Set @strSql = @strSql + 'Create table #tmp (id int)'
Set @strSql = @strSql + 'Insert into #tmp(id) values (1)'

Set @strSQL = 'Create table #tmp (id int)Insert into #tmp(id) values (1)'