大约有 36,000 项符合查询结果（耗时：0.0407秒） [XML]
NULL values inside NOT IN clause
...had one null value (bad data) which caused that query to return a count of 0 records. I sort of understand why but I could use some help fully grasping the concept.
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Getting MAC Address
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answered Oct 1 '08 at 19:06
Armin RonacherArmin Ronacher
29.6k1212 gold badges6262 silver badges6868 bronze badges
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Linux command to list all available commands and aliases
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20 Answers
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How to export and import a .sql file from command line with options? [duplicate]
...h actual server name or IP address as follows:
$ mysql -u username -p -h 202.54.1.10 databasename < data.sql
To export a database, use the following:
mysqldump -u username -p databasename > filename.sql
Note the < and > symbols in each case.
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How do I find which rpm package supplies a file I'm looking for?
...age.
sudo yum install yum-utils
repoquery --whatprovides '*bin/grep'
grep-0:2.5.1-55.el5.x86_64
grep-0:2.5.1-55.el5.x86_64
repoquery can do other queries such as listing package contents, dependencies, reverse-dependencies, etc.
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Android 4.3 Bluetooth Low Energy unstable
...hread on Samsung Galaxy S3 with Android 4.3 (at least for build JSS15J.I9300XXUGMK6)
Most devices filter advertising
Better not use android.bluetooth.BluetoothAdapter#startLeScan(UUID[] serviceUuids, LeScanCallback callback) with the parameter to filter for certain service UUIDs because this is bro...
Pointers in C: when to use the ampersand and the asterisk?
... of integers
int i = *a; // the value of the first element of a
int i2 = a[0]; // another way to get the first element
To get the second element:
int a[2]; // array
int i = *(a + 1); // the value of the second element
int i2 = a[1]; // the value of the second element
So the [] indexing operator...
Django filter queryset __in for *every* item in list
...d('Tag')
class Tag(models.Model):
name = models.CharField(max_length=50)
def __unicode__(self):
return self.name
In [2]: t1 = Tag.objects.create(name='holiday')
In [3]: t2 = Tag.objects.create(name='summer')
In [4]: p = Photo.objects.create()
In [5]: p.tags.add(t1)
In [6]: p.tags....
How do I specify local .gem files in my Gemfile?
...-1 ref
gem "foreman", git: "git://github.com/pje/foreman.git", ref: "bf648a070c"
# ...or branch
gem "foreman", git: "git://github.com/pje/foreman.git", branch: "jruby"
# ...or tag
gem "foreman", git: "git://github.com/pje/foreman.git", tag: "v0.45.0"
(As @JHurrah mentioned in his comment.)
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How to 'grep' a continuous stream?
...em with tail -f | grep, and --line-buffered solves it for me (on Ubuntu 14.04, GNU grep version 2.16). Where is the "use line buffering if stdout is a tty" logic implemented? In git.savannah.gnu.org/cgit/grep.git/tree/src/grep.c, line_buffered is set only by the argument parser.
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