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How big can a MySQL database get before performance starts to degrade
...tables. Getting a clean import of a dump file has become problematic. In order to make the process stable enough to automate, various choices needed to be made to prioritize stability over performance. If we ever had to recover from a disaster using a SQL backup, we'd be down for days.
Horizontal...
Return 0 if field is null in MySQL
... Would that be IFNULL((SELECT SUM(uop.price * uop.qty) FROM uc_order_products uop WHERE uo.order_id = uop.order_id) AS products_subtotal, 0)?
– Kevin
Oct 22 '10 at 13:46
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$PHP_AUTOCONF errors on mac os x 10.7.3 when trying to install pecl extensions
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Retrieving the last record in each group - MySQL
...TH ranked_messages AS (
SELECT m.*, ROW_NUMBER() OVER (PARTITION BY name ORDER BY id DESC) AS rn
FROM messages AS m
)
SELECT * FROM ranked_messages WHERE rn = 1;
Below is the original answer I wrote for this question in 2009:
I write the solution this way:
SELECT m1.*
FROM messages m1 LEFT...
A 'for' loop to iterate over an enum in Java
...se of lambda and streams (Tutorial):
Stream.of(Direction.values()).forEachOrdered(System.out::println);
Why forEachOrdered and not forEach with streams ?
The behaviour of forEach is explicitly nondeterministic where as the forEachOrdered performs an action for each element of this stream, in t...
Update R using RStudio
... the install.packages() function or the update.packages(function).
So, in order to install R,
go to http://www.r-project.org,
click on 'CRAN',
then choose the CRAN site that you like. I like Kansas: http://rweb.quant.ku.edu/cran/.
click on 'Download R for XXX' [where XXX is your operating syste...
Should I impose a maximum length on passwords?
... treat only the first 256/1024/2k/4k/(whatever) bytes as "significant", in order to avoid crunching on mammoth passwords.]
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Git commits are duplicated in the same branch after doing a rebase
...ev". If this is the case, then why do C5 and C6 show up before C7 in the ordering of commits on origin/dev?
– KJ50
Nov 5 '14 at 5:34
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Sorting a vector of custom objects
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Edit2: As Kappa suggests you can also sort the vector in the descending order by overloading a > operator and changing call of sort a bit:
struct MyStruct
{
int key;
std::string stringValue;
MyStruct(int k, const std::string& s) : key(k), stringValue(s) {}
bool operator...
Equivalent to 'app.config' for a library (DLL)
...}
You'll also have to add reference to System.Configuration namespace in order to have the ConfigurationManager class available.
When building the project, in addition to the DLL you'll have DllName.dll.config file as well, that's the file you have to publish with the DLL itself.
The above is ba...