Andy Kriger wrote:
> I have a file of legacy data that has duplicate entries in a column that I'd
> like to have a unique index on. How can I query to find the duplicates (so I
> can determine if they can be thrown out)?
If you have yet to learn about self joins, this is a great example of
where they are handy. Assuming a table like:
create table abc
(
id int not null, -- primary key
name text, -- duplicates are here
);
Try something like:
select b.*
from abc a, abc b
where a.id < b.id
and a.name = b.name;
HTH,
Kevin
