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How to get cumulative sum
...t2.SomeNumt) as sum
from @t t1
inner join @t t2 on t1.id >= t2.id
group by t1.id, t1.SomeNumt
order by t1.id
SQL Fiddle example
Output
| ID | SOMENUMT | SUM |
-----------------------
| 1 | 10 | 10 |
| 2 | 12 | 22 |
| 3 | 3 | 25 |
| 4 | 15 | 40 |
| 5 | 2...
MySQL/SQL: Group by date only on a Datetime column
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Cast the datetime to a date, then GROUP BY using this syntax:
SELECT SUM(foo), DATE(mydate) FROM a_table GROUP BY DATE(a_table.mydate);
Or you can GROUP BY the alias as @orlandu63 suggested:
SELECT SUM(foo), DATE(mydate) DateOnly FROM a_table GROUP BY DateOnly;...
django order_by query set, ascending and descending
How can I order by descending my query set in django by date?
11 Answers
11
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PHP Regex to check date is in YYYY-MM-DD format
I'm trying to check that dates entered by end users are in the YYYY-MM-DD. Regex has never been my strong point, I keep getting a false return value for the preg_match() I have setup.
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How are strings passed in .NET?
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A reference is passed; however, it's not technically passed by reference. This is a subtle, but very important distinction. Consider the following code:
void DoSomething(string strLocal)
{
strLocal = "local";
}
void Main()
{
string strMain = "main";
DoSomething(strMain);
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How to return smart pointers (shared_ptr), by reference or by value?
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Return smart pointers by value.
As you've said, if you return it by reference, you won't properly increment the reference count, which opens up the risk of deleting something at the improper time. That alone should be enough reason to not return ...
@Resource vs @Autowired
...th, without specifying any attributes of the annotation, perform injection by type. The difference is:
@Resource allows you to specify a name of the injected bean
@Autowired allows you to mark it as non-mandatory.
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Test if element is present using Selenium WebDriver?
...nt is present, you could try this
Boolean isPresent = driver.findElements(By.yourLocator).size() > 0
This will return true if at least one element is found and false if it does not exist.
The official documentation recommends this method:
findElement should not be used to look for non-pre...
Mean per group in a data.frame [duplicate]
...667 54.00000
Here we aggregate columns 3 and 4 of data.frame d, grouping by d$Name, and applying the mean function.
Or, using a formula interface:
aggregate(. ~ Name, d[-2], mean)
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imp...
Why does C++11's lambda require “mutable” keyword for capture-by-value, by default?
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It requires mutable because by default, a function object should produce the same result every time it's called. This is the difference between an object orientated function and a function using a global variable, effectively.
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