How about using LAG?
SELECT *,
       CASE WHEN LAG(Orderid) OVER (ORDER BY orderid, seq) = prev_orderid THEN LAG(quantity) OVER (ORDER BY orderid, seq) END AS Prev_quantity
FROM...

SSMS 17.2 is the most recent version and is compatible with all currently supported versions of SQL server (2008 - 2017).

It's unlikely you're going to get any...

Out of interest why did you start a new topic, when you have asked the question 5 days ago and others had answered? Were those answers not good enough, did...

When you say "it does not work", what do you mean? Are you presented with an error? Does the Constraint no actually drop? Does the SQL Server crash?

Personally,...

Could you explain your logic here? Why are Developers linked to the Maintenance and Director roles, why is Admin linked to Food Servies (Should this be Services?) and Manager? Why...

You say you received an error when trying to re-enable the sa account. What was this error?

Do you have any other accounts that have sysadmin privs? Generally, if...

What do you mean by "suppose another table"? Does this mean the table does not exist at this moment in time and we need to imagine that one does exist?...

Thanks Chris, but the problem was resolved. One with changing a single part of the WHERE to = 0, rather than != 3, and then my most recent post an...

Thanks, but that table definition doesn't match the table you've provided. Could you please provide CREATE and INSERT statements that work together?

I've had a look at your data,...

Could you provide a CREATE statement for your sample data please?