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What does static_assert do, and what would you use it for?
...ou can put a static assert like this
static_assert(sizeof(unsigned int) * CHAR_BIT == 32);
in your code. On another platform, with differently sized unsigned int type the compilation will fail, thus drawing attention of the developer to the problematic portion of the code and advising them to re-...
How to randomly select rows in SQL?
...
SELECT TOP 5 Id, Name FROM customerNames
ORDER BY NEWID()
That said, everybody seems to come to this page for the more general answer to your question:
Selecting a random row in SQL
Select a random row with MySQL:
SELECT...
Select random row from a sqlite table
...
Have a look at Selecting a Random Row from an SQLite Table
SELECT * FROM table ORDER BY RANDOM() LIMIT 1;
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Select first row in each GROUP BY group?
As the title suggests, I'd like to select the first row of each set of rows grouped with a GROUP BY .
17 Answers
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Initializing a member array in constructor initializer
...e about the following case, but some compilers do allow it.
struct A {
char foo[6];
A():foo("hello") { } /* valid? */
};
See this GCC PR for further details.
Do C++0x initializer lists solve the problem?
Yes, they do. However your syntax is invalid, I think. You have to use braces dir...
How to initialize a private static const map in C++?
...edef std::map<std::string, int> MyMap;
struct T {
const char* Name;
int Num;
operator MyMap::value_type() const {
return std::pair<std::string, int>(Name, Num);
}
};
static const T MapPairs[];
static const MyMap TheMap;
};
c...
How to get multiple counts with one SQL query?
...tion. This is basically the same thing as a PIVOT function in some RDBMS:
SELECT distributor_id,
count(*) AS total,
sum(case when level = 'exec' then 1 else 0 end) AS ExecCount,
sum(case when level = 'personal' then 1 else 0 end) AS PersonalCount
FROM yourtable
GROUP BY distributor_id
...
What is the email subject length limit?
How many characters are allowed to be in the subject line of Internet email?
I had a scan of The RFC for email but could not see specifically how long it was allowed to be.
I have a colleague that wants to programmatically validate for it.
...
how to use ng-option to set default value of select element
I've seen the documentation of the Angular select directive here: http://docs.angularjs.org/api/ng.directive:select .
I can't figure how to set the default value. This is confusing:
...
How to order by with union in SQL?
Is it possible to order when the data is come from many select and union it together? Such as
8 Answers
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