大约有 40,000 项符合查询结果（耗时：0.0259秒） [XML]
Simple Vim commands you wish you'd known earlier [closed]
...-search extends the functionality of * to match the whole text of a visual selection which makes it easy to search & replace the selected text, e.g. v3e (visually select 3 words) * (search) and :%s//replacement/g (replace all occurences with "replacement"). I use this so often that I have a mapp...
How to increase font size in the Xcode editor?
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Go to XCode > Preferences > Fonts & Color
From the 'Theme' box select the theme you want to modify (or select the theme you want to modify and click the "+" button at the bottom of the theme list to clone it first for backup, for there is no undo option)
In the source editor box there is...
MySQL select 10 random rows from 600K rows fast
How can I best write a query that selects 10 rows randomly from a total of 600k?
26 Answers
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Join vs. sub-query
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@JinghuiNiu Customers who bought expensive items: select custid from cust join bought using (custid) where price > 500. If a customer bought multiple expensive items, you'll get double-ups. To fix this, select custid from cust where exists (select * from bought where cust...
Nested select statement in SQL Server
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You need to alias the subquery.
SELECT name FROM (SELECT name FROM agentinformation) a
or to be more explicit
SELECT a.name FROM (SELECT name FROM agentinformation) a
share
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Cannot simply use PostgreSQL table name (“relation does not exist”)
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In other words, the following fails:
CREATE TABLE "SF_Bands" ( ... );
SELECT * FROM sf_bands; -- ERROR!
Use double-quotes to delimit identifiers so you can use the specific mixed-case spelling as the table is defined.
SELECT * FROM "SF_Bands";
Re your comment, you can add a schema to th...
How do you connect to multiple MySQL databases on a single webpage?
...d);
$dbh2 = mysql_connect($hostname, $username, $password, true);
mysql_select_db('database1', $dbh1);
mysql_select_db('database2', $dbh2);
Then to query database 1 pass the first link identifier:
mysql_query('select * from tablename', $dbh1);
and for database 2 pass the second:
mysql_query...
How can I list all foreign keys referencing a given table in SQL Server?
...get around this by creating a table, store the result into the table, then select the specific columns. Check out this link for an example :).
– John Odom
Apr 28 '15 at 19:04
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What are the differences between poll and select?
I am referring to the POSIX standard select and poll system C API calls.
3 Answers
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Jquery select all elements that have $jquery.data()
Select elements that i have previously set with jquery.data();
7 Answers
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