大约有 44,000 项符合查询结果（耗时：0.0542秒） [XML]
Which SQL query is faster? Filter on Join criteria or Where clause?
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Performance-wise, they are the same (and produce the same plans)
Logically, you should make the operation that still has sense if you replace INNER JOIN with a LEFT JOIN.
In your very case this will look like this:
SELECT *
FROM TableA a
LEFT JOIN
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Where to get “UTF-8” string literal in Java?
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In Java 1.7+, java.nio.charset.StandardCharsets defines constants for Charset including UTF_8.
import java.nio.charset.StandardCharsets;
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StandardCharsets.UTF_8.name();
For Android: minSdk 19
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How to change the type of a field?
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So simply load the document from the DB, perform the cast (new String(x)) and then save the document again.
If you need to do this programmatically and entirely from the shell, you can use the find(...).forEach(function(x) {}) syntax.
In response to the second comment below. Change the field ba...
Overriding superclass property with different type in Swift
...properties. Instead you can create an extra variable in the subclass that handles the new class type:
class Chassis {}
class RacingChassis : Chassis {}
class Car {
var chassis = Chassis()
}
class RaceCar: Car {
var racingChassis = RacingChassis()
override var chassis: Chassis {
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Capturing URL parameters in request.GET
...haha, you would use request.GET.get('q', '').
q is the parameter you want, and '' is the default value if q isn't found.
However, if you are instead just configuring your URLconf**, then your captures from the regex are passed to the function as arguments (or named arguments).
Such as:
(r'^user/(?P&...
Sorting 1 million 8-decimal-digit numbers with 1 MB of RAM
... tests already available:
http://www.theeggeadventure.com/wikimedia/index.php/Java_Data_Compression
"I ran a test to compress one million consecutive integers using
various forms of compression. The results are as follows:"
None 4000027
Deflate 2006803
Filtered 1391833
BZip2 427067
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How do you query for “is not null” in Mongo?
...rue}});
This will return all documents with both a key called "IMAGE URL" and a non-null value.
db.mycollection.find({"IMAGE URL":{$ne:null}});
Also, according to the docs, $exists currently can't use an index, but $ne can.
Edit: Adding some examples due to interest in this answer
Given these inse...
What is state-of-the-art for text rendering in OpenGL as of version 4.1? [closed]
...ype fonts into a vector texture you get this:
http://alice.loria.fr/index.php/publications.html?Paper=VTM@2005
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Run a single migration file
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Sometimes you need a './' in front of the require path, and it definitely doesn't update the schema_migrations.
– Beardo
Aug 26 '11 at 15:26
14
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Difference between Node object and Element object?
I am totally confused between Node object and Element object.
document.getElementById() returns Element object while document.getElementsByClassName()
returns NodeList object(Collection of Elements or Nodes?)
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