Sql server doesn't like the aggregate function in the set command. It does work as a SELECT and I can get the data I'm looking for so should I use that answer and try and use it as a subquery or cursor and then run the update into Customers?
The other question what is the performance difference between the 2 over larger data sets, is one better than the other? sql-server-2008 correlated-subquery partition-by asked Jun 15, 2020 at 17:20 BG1 51 1 race your horses – Zohar Peled CommentedJun 16, 2020 at 6:03
Today I came to know across a feature of SQL Server known as correlated query and noncorrelated query.Then the certain question comes in my mind: What is difference between corelated and subquery ...
This is a contrived example using SQL Server 2008. I'm essentially storing a list of ids in an xml column in a table: temp (bigint id, xml ids) I want to join the table itself to the xml nodes. ...
I have serious doubt on this answer, since most DBMS, definitely SQL Server 2008 and later, translate the single ID subquery (not correlated, meaning: not referencing multiple outer query columns) into a relatively fast semi-join. Also, as previously noted in another answer, the first, real join will return a row for EACH occurence of the matching ID in Dept - this makes no difference for a ...
There's nothing wrong with your query or the sub-query. And it is a myth that correlated-subquery's are any slower than any other correct way of doing the same thing in any modern version of SQL Server (2000 and earlier do have this problem, however). The slowness here almost certainly is coming from poor/absent indexes or other causes.
A Correlated subquery is a subquery that is evaluated once for each row processed by the outer query or main query. Execute the Inner query based on the value fetched by the Outer query all the values returned by the main query are matched.
3 The reason you were not getting the total count correctly and getting many records instead, is that the COUNT s are selected as a correlated subquery, so you will got the count for each record in the table. To fix that you have to use the aggregate function in the outer query, not from the correlated subuery.
