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Group query results by month and year in postgresql
...he "date" attribute.
sum("Sales") as "Sales" : The SUM() function adds up all the "Sales" values, and supplies a case-sensitive alias, with the case sensitivity maintained by using double-quotes.
group by 1,2 : The GROUP BY function must contain all columns from the SELECT list that are not part o...
Convert floats to ints in Pandas?
... If it's dtype then you need to create those columns as dtype object so it allows mixed, otherwise my advice would be to just use float and when doing comparisons use np.isclose
– EdChum
Jun 7 '19 at 7:46
...
Can someone explain collection_select to me in clear, simple terms?
...order(..) or something like that.
# In your example it is:
Author.all,
# then you should specify methods for generating options
:id, # this is name of method that will be called for every row, result will be set as key
:name_with_initial, # this is name of method that will be ...
How to use '-prune' option of 'find' in sh?
... test (up to and including -prune) will return false for the stuff you actually want (ie: the stuff you don't want to prune out).
Here's an example:
find . -name .snapshot -prune -o -name '*.foo' -print
This will find the "*.foo" files that aren't under ".snapshot" directories. In this example, -na...
JQuery - $ is not defined
...ge is fully loaded, and as such, before jQuery is fully loaded.
First of all, ensure, what script is call properly, it should looks like
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js" type="text/javascript"></script>
and shouldn't have attributes async...
How to declare global variables in Android?
...em you are encountering is how to save state across several Activities and all parts of your application. A static variable (for instance, a singleton) is a common Java way of achieving this. I have found however, that a more elegant way in Android is to associate your state with the Application con...
public friend swap member function
...truct vector
{
void swap(vector&) { /* swap members */ }
};
Naturally, then, our class should too, right? Well, not really. The standard library has all sorts of unnecessary things, and a member swap is one of them. Why? Let's go on.
What we should do is identify what's canonical, and w...
What is “callback hell” and how and why does RX solve it?
... clear definition together with a simple example that explains what is a "callback hell" for someone who does not know JavaScript and node.js ?
...
List of Delphi language features and version in which they were introduced/deprecated
...support in enable on Linux.
C++Builder and Delphi now use the same ABI for all calls.
Delphi 10.2 Tokyo
Support for Linux server apps (Intel 64-bit using LLVM and ARC).
Assigning a dynamic arrays to a pointer using the @ operator is only allowed when hard-casting the array.
More flexible name...
Java switch statement: Constant expression required, but it IS constant
....4 Final Variables which defines a "constant variable" as follows:
We call a variable, of primitive type or type String, that is final and initialized with a compile-time constant expression (§15.28) a constant variable. Whether a variable is a constant variable or not may have implications wit...