大约有 9,000 项符合查询结果（耗时：0.0231秒） [XML]
How to delete from select in MySQL?
...
you can use inner join :
DELETE
ps
FROM
posts ps INNER JOIN
(SELECT
distinct id
FROM
posts
GROUP BY id
HAVING COUNT(id) > 1 ) dubids on dubids.id = ps.id
...
How to return multiple values? [duplicate]
...e returning more than 1 value that are related, then it makes sense to encapsulate them into a class and then return an object of that class.
If you want to return unrelated values, then you can use Java's built-in container classes like Map, List, Set etc. Check the java.util package's JavaDoc for...
Is it secure to store passwords as environment variables (rather than as plain text) in config files
I work on a few apps in rails, django (and a little bit of php), and one of the things that I started doing in some of them is storing database and other passwords as environment variables rather than plain text in certain config files (or in settings.py, for django apps).
...
H2 in-memory database. Table not found
...KEY, FIRSTNAME VARCHAR(64), LASTNAME VARCHAR(64))");
PreparedStatement ps=connection.prepareStatement("select * from PERSON");
ResultSet r=ps.executeQuery();
if(r.next()) {
System.out.println("data?");
}
r.close();
ps.close();
s.close();
connection.close();
}
...
Is there an equivalent of 'which' on the Windows command line?
... tries the unadorned command then each of the extension ones. Hope that helps. You can tweak it to your needs as you see fit (if you want the same search order as with Windows for example - this one shows all possibilities).
– paxdiablo
Mar 26 '10 at 1:34
...
How to make pipes work with Runtime.exec()?
...
I ran into a similar problem in Linux, except it was "ps -ef | grep someprocess".
At least with "ls" you have a language-independent (albeit slower) Java replacement. Eg.:
File f = new File("C:\\");
String[] files = f.listFiles(new File("/home/tihamer"));
for (String file : fi...
Best practice for instantiating a new Android Fragment
....
This approach is also documented in the android developer reference: https://developer.android.com/reference/android/app/Fragment.html
share
|
improve this answer
|
follow...
Get started with Latex on Linux [closed]
...D$. The function $f$ is said to be \emph{continuous} on
$D$ if, for all $\epsilon > 0$ and for all $x \in D$,
there exists some $\delta > 0$ (which may depend on $x$)
such that if $y \in D$ satisfies
\[ |y - x| < \delta \]
then
\[ |f(y) - f(x)| < \epsilon. \]
One may readily verify that...
Command line to remove an environment variable from the OS level configuration
...following.
Save the PowerShell script to a file (we'll call it updateenv.ps1).
Do this from the command line: reg delete "HKCU\Environment" /v FOO /f
Run updateenv.ps1.
Close and reopen your command prompt, and you'll see that the environment variable is no longer defined.
Note, you'll probably ...
Should I be concerned about excess, non-running, Docker containers?
...r. If the container is no longer running it can still be seen with docker ps -a .
5 Answers
...