大约有 42,000 项符合查询结果（耗时：0.0467秒） [XML]
Retrieving the last record in each group - MySQL
...dowing functions, like almost all popular SQL implementations. With this standard syntax, we can write greatest-n-per-group queries:
WITH ranked_messages AS (
SELECT m.*, ROW_NUMBER() OVER (PARTITION BY name ORDER BY id DESC) AS rn
FROM messages AS m
)
SELECT * FROM ranked_messages WHERE rn = 1...
Can the Unix list command 'ls' output numerical chmod permissions?
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For creating it as an alias (example below: 'cls' command), use: alias cls="ls -l | awk '{k=0;for(i=0;i<=8;i++)k+=((substr(\$1,i+2,1)~/[rwx]/)*2^(8-i));if(k)printf(\"%0o \",k);print}'"
– danger89
Mar 6 '14 at 16:15
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Copying PostgreSQL database to another server
...o a remote host.
With a big database or a slow connection, dumping a file and transfering the file compressed may be faster.
As Kornel said there is no need to dump to a intermediate file, if you want to work compressed you can use a compressed tunnel
pg_dump -C dbname | bzip2 | ssh remoteuser@...
How can I format my grep output to show line numbers at the end of the line, and also the hit count?
...two null, - Line number : 2
example four null, - Line number : 4
Use command substitution to print out the total null count:
$ echo "Total null count :" $(grep -ic null myfile.txt)
Total null count : 2
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How to update two tables in one statement in SQL Server 2005?
...le1.LastName = 'DR. XXXXXX'
FROM Table1 T1, Table2 T2
WHERE T1.id = T2.id
and T1.id = '011008';
UPDATE Table2
SET Table2.WAprrs = 'start,stop'
FROM Table1 T1, Table2 T2
WHERE T1.id = T2.id
and T1.id = '011008';
COMMIT;
s...
How to implement OnFragmentInteractionListener
I have a wizard generated app with navigation drawer in android studio 0.8.2
12 Answers
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Create instance of generic type in Java?
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And how do you call the createContents() method?
– Alexis Dufrenoy
Aug 11 '12 at 21:36
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How to download a file from server using SSH? [closed]
...edu:foobar.txt /local/dir
replacing the username, host, remote filename, and local directory as appropriate.
If you want to access EC2 (or other service that requires authenticating with a private key), use the -i option:
scp -i key_file.pem your_username@remotehost.edu:/remote/dir/foobar.txt /l...
Sending a JSON to server and retrieving a JSON in return, without JQuery
I need to send a JSON (which I can stringify) to the server and to retrieve the resulting JSON on the user side, without using JQuery.
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Insert picture/table in R Markdown [closed]
So I want to insert a table AND a picture into R Markdown. In regular word document I can just easily insert a table (5 rows by 2 columns), and for the picture just copy and paste.
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