大约有 22,000 项符合查询结果（耗时：0.0347秒） [XML]
How to comment out a block of Python code in Vim
...' at first column with ''. <cr>:noh<cr> just clears the search string so nothing is left highlighted when you are done.
– cdated
Sep 22 '16 at 16:06
1
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Row count with PDO
...
Using this approach, fetchColumn() returns a string "1234" ... your EDIT has echo count($nRows); - count() is an array function :P. I'd also recommend type casting the result from fetchColumn() to an integer. $count = (int) $stmt->fetchColumn()
–...
Are there any downsides to passing structs by value in C, rather than passing a pointer?
...e output parameters be listed first before input parameters, e.g. int func(char* out, char *in);
– zooropa
Apr 29 '09 at 12:29
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Compare DATETIME and DATE ignoring time portion
...ng, contrived example.
--112 is ISO format 'YYYYMMDD'
declare @filterDate char(8) = CONVERT(char(8), GETDATE(), 112)
select
*
from
Sales.Orders
where
CONVERT(char(8), OrderDate, 112) = @filterDate
In a perfect world, performing any manipulation to the filtered column should be avo...
Difference between a Structure and a Union
...re that value.
union foo {
int a; // can't use both a and b at once
char b;
} foo;
struct bar {
int a; // can use both a and b simultaneously
char b;
} bar;
union foo x;
x.a = 3; // OK
x.b = 'c'; // NO! this affects the value of x.a!
struct bar y;
y.a = 3; // OK
y.b = 'c'; // OK
ed...
Does delete on a pointer to a subclass call the base class destructor?
...n this will happen when the containing object is destroyed.
class A
{
char *someHeapMemory;
public:
A() : someHeapMemory(new char[1000]) {}
~A() { delete[] someHeapMemory; }
};
class B
{
A* APtr;
public:
B() : APtr(new A()) {}
~B() { delete APtr; }
};
class C
{
A Amemb...
What's the difference between ASCII and Unicode?
...t their language (to support "é", in French, for example). Just using one extra bit doubled the size of the original ASCII table to map up to 256 characters (2^8 = 256 characters). And not 2^7 as before (128).
10000010 -> é (e with acute accent - 130)
10100000 -> á (a with acute accent - 16...
Why does Git treat this text file as a binary file?
...ut need of a null (00h) byte for anything other than the nul char (the 'C' string terminator). Thus Git's text definition is that the content (well the first 1k bytes) should not have a null byte when utf-8 encoded. Try stackoverflow.com/questions/2241348/… for a fun read. My original comment ref...
Use '=' or LIKE to compare strings in SQL?
...he (almost religious) discussion, if you should use LIKE or '=' to compare strings in SQL statements.
9 Answers
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Concatenate multiple result rows of one column into one, group by another column [duplicate]
...
Simpler with the aggregate function string_agg() (Postgres 9.0 or later):
SELECT movie, string_agg(actor, ', ') AS actor_list
FROM tbl
GROUP BY 1;
The 1 in GROUP BY 1 is a positional reference and a shortcut for GROUP BY movie in this case.
string_agg() ...