大约有 43,000 项符合查询结果（耗时：0.0297秒） [XML]
NOT IN vs NOT EXISTS
...llow NULLs the NOT IN will be treated identically to the following query.
SELECT ProductID,
ProductName
FROM Products p
WHERE NOT EXISTS (SELECT *
FROM [Order Details] od
WHERE p.ProductId = od.ProductId)
The exact plan may vary but for my examp...
Ruby on Rails form_for select field with class
I am beating my head against the wall on this one. I want to make a simple select tag using the f.select tag but nothing I do works. I put an example below:
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Android Spinner: Get the selected item change event
How can you set the event listener for a Spinner when the selected item changes?
16 Answers
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Where's my JSON data in my incoming Django request?
...'/event/save-json/',
type: 'POST',
contentType: 'application/json; charset=utf-8',
data: $.toJSON(myEvent),
dataType: 'text',
success: function(result) {
alert(result.Result);
}
});
Django:
def save_events_json(request):
if request.is_ajax():
if request...
Can I set an unlimited length for maxJsonLength in web.config?
...retrieve the list of more then 17000 records (each won't have more than 10 char length), it's exceeding the length and throws the error:
...
Fast way to discover the row count of a table in PostgreSQL
...in your case.
Instead of getting the exact count (slow with big tables):
SELECT count(*) AS exact_count FROM myschema.mytable;
You get a close estimate like this (extremely fast):
SELECT reltuples::bigint AS estimate FROM pg_class where relname='mytable';
How close the estimate is depends on ...
Best way to strip punctuation from a string
...or ch in s if ch not in exclude)
This is faster than s.replace with each char, but won't perform as well as non-pure python approaches such as regexes or string.translate, as you can see from the below timings. For this type of problem, doing it at as low a level as possible pays off.
Timing cod...
Build Android Studio app via command line
... an emulator)
Bonus
I set up an alias in my ~/.bash_profile, to make it a 2char command.
alias bi="gradlew && adb install -r exampleApp.apk"
(Short for Build and Install)
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What is the simplest SQL Query to find the second largest value?
...
SELECT MAX( col )
FROM table
WHERE col < ( SELECT MAX( col )
FROM table )
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Fastest way to determine if record exists
...
SELECT TOP 1 products.id FROM products WHERE products.id = ?; will outperform all of your suggestions as it will terminate execution after it finds the first record.
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