Would you mind to open BOL?

Or you prefer somebody else to do it for you and copy-paste the topic here?

Why you need GROUP BY at all?

What do you mean "no significant difference"?

3 or 4 times faster (according to your own tests) is not significant difference for you?

Your answer is definetely wrong.

Another question - why to even...

Who gave you an idea about BEGIN TRAN?

Kill him.

UPDATE is a transaction itself.

If you would bother to read posts above you'd figure out why you SHOULD NOT use transactions.

Database is not the place where files must be edited.

There are text editors for this.

Learn how to use NULLs.

It's more flexible and more effective.

1. Insert only if the record with the same values does not exists.

2. Retrieve ID of the record with values inserted(existing).

If you need to use SCOPE_UDENTITY you're doing bad. Your...

Are you sure your investigation is really useful?

Gaining 2ms, o-oh, sorry, 3 ms on 50 mil rows table - do you beleive it really worth the efforts?

What kind of question...

David,

you're clearly wrong.

2 days ago I just updated 1,2 mil. rows on production system using this approach.

No one was locked. No one even noticed. Yes, it took whole day,...

You shuold NOT use keyword DISTINCT in views unless it's a view for user interface.

Duplicate rows mean you've got mess in your data. Clean it up.

SELECT Idetifier

INTO #ToUpdate

FROM Table

WHERE <Update Criteria>

WHILE EXISTS(select 1 from ToUpdate)

BEGIN

SET ROWCOUNT 1000

SELECT Identifier

INTO #CurrentUPDATE

FROM #ToUpdate

SET ROWCOUNT 0

UPDATE Table

SET ...

FROM #CurrentUPDATE

WHERE Table.Identifier = CurrentUPDATE.Identifier

DELETE FROM #ToUpdate

WHERE EXISTS (select 1 from...

Don't think. It's really bad habit.

Let horses think, their heads are much bigger.

Better try you suggessions.

Still no time to open BOL?

No, if you'v got shares in Intel or/and HP.

Are you sure your solution is simpler than mine?

Can you make the length of returned string to be changed from 10 to, say, 8 without rewriting script, just by supplying...