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Counting DISTINCT over multiple columns
...INCT concat(DocumentId, DocumentSessionId)) FROM DocumentOutputItems;
In MySQL you can do the same thing without the concatenation step as follows:
SELECT count(DISTINCT DocumentId, DocumentSessionId) FROM DocumentOutputItems;
This feature is mentioned in the MySQL documentation:
http://dev.my...
How do I find all files containing specific text on Linux?
... "show the file name, not the result itself".
/ stands for starting at the root of your machine.
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How to check if a process id (PID) exists
...wo ways:
Lets start by looking for a specific application in my laptop:
[root@pinky:~]# ps fax | grep mozilla
3358 ? S 0:00 \_ /bin/sh /usr/lib/firefox-3.5/run-mozilla.sh /usr/lib/firefox-3.5/firefox
16198 pts/2 S+ 0:00 \_ grep mozilla
All examples now will look...
What is the difference between a schema and a table and a database?
...ction of tables. A DBMS (Database Management System) is the software (like MySQL, SQL Server, Oracle, etc) that manages and runs a database.
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苦逼的年轻人和年薪百万的区别到底在哪里？ - 杂谈 - 清泛网 - 专注C/C++及内核技术
...进录取率极低的计算机科学学院，学弟学妹组队求经验，如何管住自己刻苦学习，他说不出来，我教他，“你当时一天自习七小时，为保证自己避过食堂高峰期，六点前吃饱入座，带一袋牛肉干，防止后期因为饥饿影响效率，是...
Given two directory trees, how can I find out which files differ by content?
...les in subdirs, for example rsync --options /usr /bin /var /sbin /lib /old_root will effectively compare current root / (by specifying all subdirs in it) and /old_root (containing for example some older backup of /), which is something diff -r can't do. And if you assume that files with same size, ...
Validating with an XML schema in Python
...
from the tests on http://lxml.de/api/lxml.tests.test_dtd-pysrc.html
...
root = etree.XML(_bytes("<b/>"))
dtd = etree.DTD(BytesIO("<!ELEMENT b EMPTY>"))
self.assert_(dtd.validate(root))
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How to drop all user tables?
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Being new to Oracle and I'm more familiar with MySQL; reseting a DB seems difficult. IN MySQL a USER is separate to a DATABASE. DROP USER username CASCADE worked for me. But in MySQL all I would have to do is DROP DATABASE and create a new one
– gawp...
Log exception with traceback
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raise
Now looking at the log file, /tmp/logging_example.out:
DEBUG:root:This message should go to the log file
ERROR:root:Got exception on main handler
Traceback (most recent call last):
File "/tmp/teste.py", line 9, in <module>
run_my_stuff()
NameError: name 'run_my_stuff' is no...
Find location of a removable SD card
...ally 'contact the manufacturer'. Not useful.
– dragonroot
Mar 15 '12 at 2:05
6
The last part of t...