大约有 43,200 项符合查询结果（耗时：0.0456秒） [XML]
Understanding the Event Loop
...
1: If we are talking about a single-threaded application, then what processes setTimeouts while JS engine accepts more requests and executes them? Isn't that single thread will continue working on other requests? Then who is ...
How do shift operators work in Java? [duplicate]
...
214
System.out.println(Integer.toBinaryString(2 << 11));
Shifts binary 2(10) by 11 times t...
Counting null and non-null values in a single query
... to get it to work on another RDBMS):
select sum(case when a is null then 1 else 0 end) count_nulls
, count(a) count_not_nulls
from us;
Or:
select count(*) - count(a), count(a) from us;
share
|
...
Find rows that have the same value on a column in MySQL
...SELECT email,
count(*) AS c
FROM TABLE
GROUP BY email
HAVING c > 1
ORDER BY c DESC
If you want the full rows:
select * from table where email in (
select email from table
group by email having count(*) > 1
)
...
How to use shared memory with Linux in C
...
166
There are two approaches: shmget and mmap. I'll talk about mmap, since it's more modern and fl...
PHP: How to send HTTP response code?
...TP response line and lets you replace that with a custom one
header("HTTP/1.1 200 OK");
However, this requires special treatment for (Fast)CGI PHP:
$sapi_type = php_sapi_name();
if (substr($sapi_type, 0, 3) == 'cgi')
header("Status: 404 Not Found");
else
header("HTTP/1.1 404 Not Found");...
Can't pickle when using multiprocessing Pool.map()
...
12 Answers
12
Active
...
How to define a function in ghci across multiple lines?
...
125
For guards (like your example), you can just put them all on one line and it works (guards do ...
snprintf and Visual Studio 2010
I'm unfortunate enough to be stuck using VS 2010 for a project, and noticed the following code still doesn't build using the non-standards compliant compiler:
...