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Group query results by month and year in postgresql
...ar from date) as yyyy,
sum("Sales") as "Sales"
from yourtable
group by 1,2
At the request of Radu, I will explain that query:
to_char(date,'Mon') as mon, : converts the "date" attribute into the defined format of the short form of month.
extract(year from date) as yyyy : Postgresql's "ext...
How to select a drop-down menu value with Selenium using Python?
...le:
from selenium import webdriver
b = webdriver.Firefox()
b.find_element_by_xpath("//select[@name='element_name']/option[text()='option_text']").click()
You can read more in:
https://sqa.stackexchange.com/questions/1355/unable-to-select-an-option-using-seleniums-python-webdriver
...
Examples of GoF Design Patterns in Java's core libraries
...esign patterns in Wikipedia. It also mentions which patterns are mentioned by GoF. I'll sum them up here and try to assign as many pattern implementations as possible, found in both the Java SE and Java EE APIs.
Creational patterns
Abstract factory (recognizeable by creational methods returning the...
How to use GROUP BY to concatenate strings in MySQL?
...
SELECT id, GROUP_CONCAT(name SEPARATOR ' ') FROM table GROUP BY id;
http://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html#function_group-concat
From the link above, GROUP_CONCAT: This function returns a string result with the concatenated non-NULL values from a group. It re...
How to sum a variable by group
...
Using aggregate:
aggregate(x$Frequency, by=list(Category=x$Category), FUN=sum)
Category x
1 First 30
2 Second 5
3 Third 34
In the example above, multiple dimensions can be specified in the list. Multiple aggregated metrics of the same data type can ...
Order a MySQL table by two columns
How do I sort a MySQL table by two columns?
5 Answers
5
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Passing a String by Reference in Java?
... @Boris Pavlovic - yes, but unless the same StringBuilder is used by different threads, which IMO is unlikely in any given scenario, it should not be a problem. It doesn't matter if the method is called by different threads, receiving different StringBuilder.
– Ravi Wa...
How do I pass a unique_ptr argument to a constructor or a function?
...a unique pointer as an argument, as well as their associated meaning.
(A) By Value
Base(std::unique_ptr<Base> n)
: next(std::move(n)) {}
In order for the user to call this, they must do one of the following:
Base newBase(std::move(nextBase));
Base fromTemp(std::unique_ptr<Base>(ne...
How can I multiply and divide using only bit shifting and adding?
...y in terms of adding and shifting you want to decompose one of the numbers by powers of two, like so:
21 * 5 = 10101_2 * 101_2 (Initial step)
= 10101_2 * (1 * 2^2 + 0 * 2^1 + 1 * 2^0)
= 10101_2 * 2^2 + 10101_2 * 2^0
= 10101_2 << 2 + 10101_2 << 0 (De...
Swift how to sort array of custom objects by property value
...t 2
images.sorted({ $0.fileID > $1.fileID })
Swift 3+
images.sorted(by: { $0.fileID > $1.fileID })
The example above gives desc sort order
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