Pros and cons of using a cursor (in SQL server)

Question

I asked a question here Using cursor in OLTP databases (SQL server)

where people responded saying cursors should never be used.

I feel cursors are very powerful

Answer 1

In general cursors are a bad thing. However in some cases it is more practical to use a cursor and in some it is even faster to use one. A good example is a cursor through a contact table sending emails based on some criteria. (Not to open up the question if sending an email from your DBMS is a good idea - let's just assume it is for the problem at hand.) There is no way to write that set-based. You could use some trickery to come up with a set-based solution to generate dynamic SQL, but a real set-based solution does not exist.

However, a calculation involving the previous row can be done using a self join. That is usually still faster than a cursor.

In all cases you need to balance the effort involved in developing a faster solution. If nobody cares, if you process runs in 1 minute or in one hour, use what gets the job done quickest. If you are looping through a dataset that grows over time like an [orders] table, try to stay away from a cursor if possible. If you are not sure, do a performance test comparing a cursor base with a set-based solution on several significantly different data sizes.