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ORA-00979 not a group by expression
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You must put all columns of the SELECT in the GROUP BY or use functions on them which compress the results to a single value (like MIN, MAX or SUM).
A simple example to understand why this happens: Imagine you have a database like this:
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how to restart only certain processes using supervisorctl?
...rvisor.rpcinterface:make_main_rpcinterface
supervisorctl command can be called with a group name:
supervisorctl restart foo:
as well as with multiple process names:
supervisorctl restart foo:cat1 cat2
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java: Class.isInstance vs Class.isAssignableFrom
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Both answers are in the ballpark but neither is a complete answer.
MyClass.class.isInstance(obj) is for checking an instance. It returns true when the parameter obj is non-null and can be cast to MyClass without raising a ClassCastException. In ot...
How do I move a redis database from one server to another?
...file named dump.rdb in the same folder as your redis server. See a list of all server commands.
Copy this dump.rdb to the other redis server you want to migrate to. When redis starts up, it looks for this file to initialize the database from.
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Read lines from a file into a Bash array [duplicate]
... from BinaryZebra's comment
and tested here. The addition of command eval allows for the expression to be kept in the present execution environment while the expressions before are only held for the duration of the eval.
Use $IFS that has no spaces\tabs, just newlines/CR
$ IFS=$'\r\n' GLOBIGNORE=...
Java generics - why is “extends T” allowed but not “implements T”?
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To add to the confusion getFoo(List<? super Foo> fooList) ONLY works with the class that literally are extended by Foo like class Foo extends WildcardClass. In this case a List<WildcardClass> would be acceptable input. However any class...
How to detect if URL has changed after hash in JavaScript
...hange event on window.
In some old browsers, you need a timer that continually checks location.hash. If you're using jQuery, there is a plugin that does exactly that.
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Comment Inheritance for C# (actually any language)
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Automatically generated docs seem like a very bad idea to me. They don't add any useful information but only blow up the code unnecessarily. If a tool can understand what a method does from its name, than a person can also understand ...
regex for matching something if it is not preceded by something else
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You want to use negative lookbehind like this:
\w*(?<!foo)bar
Where (?<!x) means "only if it doesn't have "x" before this point".
See Regular Expressions - Lookaround for more information.
Edit: added the \w* to capture the characters before (e.g. "beach").
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Should I pass an std::function by const-reference?
...rmance, pass by value if you are storing it.
Suppose you have a function called "run this in the UI thread".
std::future<void> run_in_ui_thread( std::function<void()> )
which runs some code in the "ui" thread, then signals the future when done. (Useful in UI frameworks where the UI ...