大约有 40,000 项符合查询结果（耗时：0.0826秒） [XML]
Counting null and non-null values in a single query
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If I understood correctly you want to count all NULL and all NOT NULL in a column...
If that is correct:
SELECT count(*) FROM us WHERE a IS NULL
UNION ALL
SELECT count(*) FROM us WHERE a IS NOT NULL
Edited to have the full query, after reading the comments :]
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javax.faces.application.ViewExpiredException: View could not be restored
...ession cookie is not maintained anymore for some reason in browser, or by calling HttpSession#invalidate() in server, or due a server specific bug with session cookies as known in WildFly), then the serialized view state is not available anymore in the session and the enduser will get this exception...
How to tell if a string contains a certain character in JavaScript?
...tion does. There are a lot of people who don't understand regex, and generally the simpler answer is the best.
– kemiller2002
Oct 13 '15 at 19:19
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How to prevent UINavigationBar from covering top of view in iOS 7?
After updating to Xcode 5, the navigation bars in all of my app's views have shifted down. Here are some screenshots, the first showing everything in the view as it's pulled down, and the second showing all of it untouched. The search bar should begin where the navigation bar.
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How to get nth jQuery element
...epends on the desired behavior. $('select').find('option').eq(n) will basically ignore the grouping, and get all options as a whole. If you want it per group, something like this is necessary: $('select').find('optgroup').each(function() { $(this).find('option').eq(n)...; })
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Can JSON start with “[”?
From what I can read on json.org , all JSON strings should start with { (curly brace), and [ characters (square brackets) represent an array element in JSON.
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Gradle buildscript dependencies
... level are used to fetch the dependencies that your project depends on. So all the dependencies you need to compile your project.
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Django dump data for a single model?
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As of version 1.1 and greater, the Django dumpdata management command allows you to dump data from individual tables:
./manage.py dumpdata myapp1 myapp2.my_model
You can also separate multiple apps and models on the command line. Here's the canonical definition:
django-admin dumpdata [app_l...
PersistentObjectException: detached entity passed to persist thrown by JPA and Hibernate
... be "Property". Best practice to declare "Property" access type is to move ALL the annotations from the member properties to the corresponding getters. A big word of caution is not to mix "Field" and "Property" access types within the entity class otherwise the behavior is undefined by the JSR-317 s...
List the queries running on SQL Server
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You can run the sp_who command to get a list of all the current users, sessions and processes. You can then run the KILL command on any spid that is blocking others.
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