大约有 31,500 项符合查询结果（耗时：0.0507秒） [XML]
Select n random rows from SQL Server table
...the key scan of values plus the join cost, which on a large table with a small percentage selection should be reasonable.
share
|
improve this answer
|
follow
...
How can I get a list of build targets in Ant?
... the available built targets without having to search through the file manually. Does ant have a command for this - something like ant show-targets - that will make it list all the targets in the build file?
...
Is there a way to make npm install (the command) to work behind proxy?
...roxy variable in a .npmrc file but it does not work. Trying to avoid manually downloading all require packages and installing.
...
Is there a simple way to delete a list element by value?
...('b')
>>> print(a)
['a', 'c', 'd']
Mind that it does not remove all occurrences of your element. Use a list comprehension for that.
>>> a = [10, 20, 30, 40, 20, 30, 40, 20, 70, 20]
>>> a = [x for x in a if x != 20]
>>> print(a)
[10, 30, 40, 30, 40, 70]
...
Clearing using jQuery
...
Easy: you wrap a <form> around the element, call reset on the form, then remove the form using .unwrap(). Unlike the .clone() solutions otherwise in this thread, you end up with the same element at the end (including custom properties that were set on it).
Tested and wo...
When is assembly faster than C?
...hat although that's not entirely false, the cases where assembler can actually be used to generate more performant code are both extremely rare and require expert knowledge of and experience with assembly.
...
Why is Python running my module when I import it, and how do I stop it?
...program I'm building that can be run in either of 2 ways: the first is to call "python main.py" which prompts the user for input in a friendly manner and then runs the user input through the program. The other way is to call "python batch.py -file- " which will pass over all the friendly input gat...
Map.clear() vs new Map : Which one will be better? [duplicate]
...stance, which is backed with new array. So, garbage collector should clear all the key and values from the previous map, and clear the reference to itself. So O(n) algorithm is executed anyway, but in the garbage collector thread. For 1000 records you won't see any difference.
BUT. The performance ...
private final static attribute vs private final attribute
...riable);
That makes the behaviour much more obvious. Modern IDEs will usually suggest changing the second listing into the third.
There is no reason to have an inline declaration initializing the value like the following, as each instance will have its own NUMBER but always with the same value (i...
Change app language programmatically in Android
Is it possible to change the language of an app programmatically while still using Android resources?
35 Answers
...