大约有 40,000 项符合查询结果（耗时：0.0391秒） [XML]
LEFT JOIN only first row
...
If you can assume that artist IDs increment over time, then the MIN(artist_id) will be the earliest.
So try something like this (untested...)
SELECT *
FROM feeds f
LEFT JOIN artists a ON a.artist_id = (
SELECT
MIN(fa.artist_id) a_id
FROM feeds_artists fa
WHERE fa.feed_id = ...
What are naming conventions for MongoDB?
...tation mentions you may use underscores, also built-in identifier is named _id (but this may be be to indicate that _id is intended to be private, internal, never displayed or edited.
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impro...
How do I use installed packages in PyCharm?
...ere you can import the module.
>> import gnuradio
>> gnuradio.__file__
"path/to/gnuradio"
Most commonly you'll have a folder structure like this:
foobarbaz/
gnuradio/
__init__.py
other_file.py
You want to add foobarbaz to the path here.
...
Removing colors from output
...all conceivable ANSI escape sequences:
./somescript | sed 's/\x1B[@A-Z\\\]^_]\|\x1B\[[0-9:;<=>?]*[-!"#$%&'"'"'()*+,.\/]*[][\\@A-Z^_`a-z{|}~]//g'
(and if you have @edi9999's SI problem, add | sed "s/\x0f//g" to the end; this works for any control char by replacing 0f with the hex of the u...
How do I change the string representation of a Python class? [duplicate]
...
The closest equivalent to Java's toString is to implement __str__ for your class. Put this in your class definition:
def __str__(self):
return "foo"
You may also want to implement __repr__ to aid in debugging.
See here for more information:
Special Method Names - Basic Cu...
Difference between -pthread and -lpthread while compiling
...nopthread.txt
$ diff dm.pthread.txt dm.nopthread.txt
152d151
< #define _REENTRANT 1
208d206
< #define __USE_REENTRANT 1
Using the -lpthread option only causes the pthread library to be linked - the pre-defined macros don't get defined.
Bottom line: you should use the -pthread option.
No...
使用TokuMX配置Replica Set集群 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...e，可加参数指定ip、端口，默认本机27017）
config={
"_id" : "ReplSetName",
"members" : [
{"_id" : 0, "host" : "172.16.88.97:27017",priority:2},
{"_id" : 1, "host" : "172.16.88.97:27018",priority:1},
{"_id" : 2, "host" : "172.16.88.97:27019",arbit...
How to debug a Flask app
...e browser when there is an error. To run in development mode, set the FLASK_ENV=development environment variable then use the flask run command (remember to point FLASK_APP to your app as well).
For Linux, Mac, Linux Subsystem for Windows, Git Bash on Windows, etc.:
export FLASK_APP=myapp
export F...
How to generate a random number in C++?
...d
(assuming rand() itself is uniformly distributed from 0 to RAND_MAX) */
while( ( n = rand() ) > RAND_MAX - (RAND_MAX-5)%6 )
{ /* bad value retrieved so get next one */ }
printf( "%d,\t%d\n", n, n % 6 + 1 );
}
return 0;
}
^^^ THAT sequence from a sing...
How to extract a substring using regex
...a i want' inside 'and even more data'"
text.split("'").zipWithIndex.filter(_._2 % 2 != 0).map(_._1)
res: Array[java.lang.String] = Array(the data i want, and even more data)
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