How can I make a SQL temp table with primary key and auto-incrementing field?

If you're just doing some quick and dirty temporary work, you can also skip typing out an explicit CREATE TABLE statement and just make the temp table with a SELECT...INTO and include an Identity field in the select list.

select IDENTITY(int, 1, 1) as ROW_ID,
       Name
into #tmp
from (select 'Bob' as Name union all
      select 'Susan' as Name union all
      select 'Alice' as Name) some_data

select *
from #tmp

you dont insert into identity fields. You need to specify the field names and use the Values clause

insert into #tmp (AssignedTo, field2, field3) values (value, value, value)

If you use do a insert into... select field field field it will insert the first field into that identity field and will bomb

You are just missing the words "primary key" as far as I can see to meet your specified objective.

For your other columns it's best to explicitly define whether they should be NULL or NOT NULL though so you are not relying on the ANSI_NULL_DFLT_ON setting.

CREATE TABLE #tmp
(
ID INT IDENTITY(1, 1) primary key ,
AssignedTo NVARCHAR(100),
AltBusinessSeverity NVARCHAR(100),
DefectCount int
);

insert into #tmp 
select 'user','high',5 union all
select 'user','med',4


select * from #tmp