but it cannot index on ids. So the ids would have to be pulled out of the index and filtered. This would only be useful if the condition on created_at is very narrow and the most selctive in the query. Looking at the row counts in your EXPLAIN, I don't feel this is the case...
expensive part is due to the fact that one on of the sides has a big residual. And in this...
In the picture above, we can see that the scan operator is reused, but there is still a duplicate computing part (a > 10) after sub-plan reuse. It's very hard for the optimizer to find the duplicate computing expression in an operator, especially when the query is complex and various ...
Anonymous February 01, 2014 Comment for Number 1 is wrong. SQL Server just needs to scan the leaf level of the smallest non-clustered index, which can be very fast. Anonymous June 19, 2014 Very cool - thanks... This helps a lot Anonymous July 29, 2014 Very nice query t...
Thanks for your answers so far. I have created indexes for all the foreign keys and added a primary key to publicationtypes and audittypes tables (oops, that was silly) Anyway here is the new explain And this is the where/from part of the query (sorry the formatting get's lost...
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performance and to scale your application, you are going to need to know how to optimize it. Even before you worry about caching or replication, your queries need to be lightning fast. All that helps, but it does nothing to help you on the first query. So how do you fix your queries...
As a developer, sooner or later you are going to want to take advantage of the FAST Query Language also known as FQL. This lets you truly leverage the power of FAST and perform very advanced queries. I’ve shown you how to use the KeywordQuery cl...
Add Time in SQL HH:MM:SS to another HH:MM:SS Adding a column to a large (100 million rows) table with default constraint adding a extra column in a pivot table created uisng T-SQL Pivot Table query Adding a partition scheme to an existing table. Adding a Value to a 'date' Column...
I mentioned the word recursive, but that doesn’t mean that the query should be recursive, but conceptually it is. The query should be as fast as possible. The structure of the tables may need to be changed as well. Thanks for your help!