June 2015
Intermediate to advanced
1800 pages
70h 6m
English
book
Microsoft SQL Server 2014 Unleashed
by Ray Rankins, Paul Bertucci, Chris Gallelli, Alex T. Silverstein
Content preview from Microsoft SQL Server 2014 UnleashedBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Estimating Rows Using Index Statistics
How does the Query Optimizer use the index statistics to estimate the number of rows that match the SARGs in a query?
SQL Server uses the histogram information when searching for a known value being compared to the leading column of the index key column, especially when the search spans a range or when there are duplicate values in the key. Consider this query on the Person table in the AdventureWorks2012 database:
select * from Person where LastName = 'Alexander'
Because the LastName values in the table are not unique, SQL Server uses the histogram on LastName (refer to Listing 32.2) to estimate the number of matching rows. For the value of 'Alexander', it would look at ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.