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UPDATE multiple tables in MySQL using LEFT JOIN
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See the article in my blog for performance details:
Finding incomplete orders: performance of LEFT JOIN compared to NOT IN
Unfortunately, MySQL does not allow using the target table in a subquery in an UPDATE statement, that's why you'll need to stick to less efficient LEFT JOIN syntax.
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Remove duplicate rows in MySQL
...owing columns:
employee (id, first_name, last_name, start_date, ssn)
In order to delete the rows with a duplicate ssn column, and keeping only the first entry found, the following process can be followed:
-- create a new tmp_eployee table
CREATE TABLE tmp_employee LIKE employee;
-- add a unique...
Idiomatic way to convert an InputStream to a String in Scala
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This is potentially an order of magnitude faster than scala.io.Source in Scala 2.11.7. I wrote a really basic benchmark of it and most of the time, it was about 5% faster for large files (test was ~35 MB text file) all the way up to 2,800% faster f...
Convert line-endings for whole directory tree (Git)
... them.... instead I had to d/l from here rpmfind.net/linux/rpm2html/search.php?query=dos2unix
– Kerridge0
Aug 20 '13 at 18:20
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cannot convert data (type interface {}) to type string: need type assertion
...Even if i is an interface type, []i is not interface type. As a result, in order to convert []i to its value type, we have to do it individually:
// var items []i
for _, item := range items {
value, ok := item.(T)
dosomethingWith(value)
}
Performance
As for performance, it can be slower ...
JMS Topic vs Queues
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As for the order preservation, see this ActiveMQ page. In short: order is preserved for single consumers, but with multiple consumers order of delivery is not guaranteed.
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What is the best way to iterate over a dictionary?
...is completely undeserving of so many upvotes. A dictionary has no implicit order, so using .ElementAt in this context might lead to subtle bugs. Far more serious is Arturo's point above. You'll be iterating the dictionary dictionary.Count + 1 times leading to O(n^2) complexity for an operation that ...
Haskell Type vs Data Constructor
... data or newtype (e.g. data Bright = Bright Color), or you can use type in order to define a synonym (e.g. type Bright = Color).
– Landei
Dec 16 '14 at 12:59
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Installing Bootstrap 3 on Rails App
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Doesn't the order of the require statements in the application.css file control the order in which files are loaded rather than the order of the directories in the path list? The order of the paths typcially controls which version of a ...
Is there a Max function in SQL Server that takes two values like Math.Max in .NET?
... isnull(@val2,@val1)
end
... and you would call it like so ...
SELECT o.OrderId, dbo.InlineMax(o.NegotiatedPrice, o.SuggestedPrice)
FROM Order o
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