Hi Lynn

That sort of works but when I run just this part for the second time I get.

Msg 2627, Level 14, State 1, Line 2

Violation of PRIMARY KEY constraint 'PK__RefTable__6897329A11007AA7'. Cannot insert duplicate key in object 'dbo.RefTable'.

The statement has been terminated.

insert into RefTable(software_name_raw,software_name_amended)

select

bt.software_name_raw,

'Needs Updating'

from

BigTable bt

where

not exists(select 1 from RefTable rf where rf.software_name_raw = bt.software_name_raw);

select * from RefTable;

update bt set

software_name_raw = rt.software_name_amended

from

BigTable bt

inner join RefTable rt

on (bt.software_name_raw = rt.software_name_raw)

where

rt.software_name_amended <> 'Needs Updating';

select * from BigTable;

GO