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Find difference between timestamps in seconds in PostgreSQL
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Try:
SELECT EXTRACT(EPOCH FROM (timestamp_B - timestamp_A))
FROM TableA
Details here: EXTRACT.
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How to create war files
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I've always just selected Export from Eclipse. It builds the war file and includes all necessary files. Providing you created the project as a web project that's all you'll need to do. Eclipse makes it very simple to do.
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How to limit the amount of concurrent async I/O operations?
...syncThreadCount);
IEnumerable<Task> tasks = inputEnumerable.Select(async input =>
{
await throttler.WaitAsync().ConfigureAwait(false);
try
{
await asyncProcessor(input).ConfigureAwait(false);
}
fina...
Python: Get relative path from comparing two absolute paths
...PurePath.parents()), taking the intersection of all these parent sets, and selecting the longest common prefix.
PPPPPS: Python 3.5 introduced a proper solution to this question: os.path.commonpath(), which returns a valid path.
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data.table vs dplyr: can one do something well the other can't or does poorly?
... ## data.table syntax
left_join(DT2, DT1) ## dplyr syntax
# 2. select columns while join
DT1[DT2, .(z, i.mul)]
left_join(select(DT2, x, y, mul), select(DT1, x, y, z))
# 3. aggregate while join
DT1[DT2, .(sum(z) * i.mul), by = .EACHI]
DF1 %>% group_by(x, y) %>% summarise(z = su...
How do malloc() and free() work?
...n limitations.
Why does your code crash:
The reason is that by writing 9 chars (don't forget the trailing null byte) into an area sized for 4 chars, you will probably overwrite the administrative-data stored for another chunk of memory that resides "behind" your chunk of data (since this data is m...
Table Naming Dilemma: Singular vs. Plural Names [closed]
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Customer
Customer.CustomerID
CustomerAddress
public Class Customer {...}
SELECT FROM Customer WHERE CustomerID = 100
Once you know you are dealing with "Customer", you can be sure you will use the same word for all of your database interaction needs.
Reason 5. (Globalization). The world is gettin...
How to prevent IFRAME from redirecting top-level window
... The user will not know why this confirmation appears, and will probably select a random response. I don't recommend using it. There are other solutions- the sandbox.
– oriadam
Dec 6 '15 at 23:10
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Can you test google analytics on a localhost address?
...lag is around 1 minute until the data is shown on the page, as long as you select the current day.
For example, you create Site and Site Test, and each one ha UA-XXXX-Y code.
In your application logic, where you serve the analytics JavaScript, check your environment and for production use your Sit...
MySQL: Sort GROUP_CONCAT values
... see http://dev.mysql.com/doc/refman/...tions.html#function_group-concat:
SELECT student_name,
GROUP_CONCAT(DISTINCT test_score ORDER BY test_score DESC SEPARATOR ' ')
FROM student
GROUP BY student_name;
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