Insert - select error

Question

I created a table like this...emp_id is primary key.
CREATE TABLE [dbo].[employee] (
[emp_id] [numeric](18, 0) NOT NULL ,
[emp_name] [varchar] (8) NULL ,
[emp_address] [varchar] (128) NULL ,
) ON [PRIMARY]
GO
when i try to execute this sql....i get an error.
insert employee (emp_id,emp_name,emp_address)
select distinct emp_id,emp_name,emp_address
from external_table
where emp_id is not null
order by emp_id
Error is...
Server: Msg 2627, Level 14, State 1, Line 1
Violation of PRIMARY KEY constraint 'PK_employee'. Cannot
insert duplicate key in object 'employee'.
The statement has been terminated.
why i get this error?. I checked data...there is no duplicate
data.

Answer 1

quote:
Originally posted by:
Javagene
i tried to use Dan's sql.
insert into employee
(emp_id,emp_name,emp_address)
select emp_id, max(emp_name), max(emp_address)
from external_table
where emp_id is not null
group by emp_id
i got 6 fileds....so i need max for all those fields for
working this query?.
Yes. That might also merge fields from different records.
Which may not produce the results you'd expect.
Another option. If your external table doesn't have a unique
key, you can create one by inserting the records into a temp table
with an identity column.
CREATE TABLE #TempExternalTable (
TheUniqueKey int identity,
[emp_id] [numeric](18, 0) NOT NULL ,
[emp_name] [varchar] (8) NULL ,
[emp_address] [varchar] (128) NULL ,
GO
Then use
insert employee (emp_id,emp_name,emp_address)
Select e.emp_id, e.emp_name, e.emp_address
from #TempExternalTable e
inner join (
Select emp_id, max(TheUniqueKey) AS MaxUniqueKey
from #TempExternalTable
group by emp_id
as t on t.MaxUniqueKey = e.TheUniquekey
Edit - table name correction