大约有 41,000 项符合查询结果（耗时：0.0461秒） [XML]
Simulate CREATE DATABASE IF NOT EXISTS for PostgreSQL?
...k around it from within psql by executing the DDL statement conditionally:
SELECT 'CREATE DATABASE mydb'
WHERE NOT EXISTS (SELECT FROM pg_database WHERE datname = 'mydb')\gexec
The manual:
\gexec
Sends the current query buffer to the server, then treats each column of each row of the query's outpu...
How to find elements by class
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CSS selectors
single class first match
soup.select_one('.stylelistrow')
list of matches
soup.select('.stylelistrow')
compound class (i.e. AND another class)
soup.select_one('.stylelistrow.otherclassname')
soup.select('.st...
MySQL Select minimum/maximum among two (or more) given values
Is it possible to SELECT the minimum or maximum among two or more values. I'd need something like this:
4 Answers
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How to subtract 30 days from the current datetime in mysql?
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SELECT * FROM table
WHERE exec_datetime BETWEEN DATE_SUB(NOW(), INTERVAL 30 DAY) AND NOW();
http://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html#function_date-add
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Return rows in random order [duplicate]
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SELECT * FROM table
ORDER BY NEWID()
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Select last N rows from MySQL
I want to select last 50 rows from MySQL database within column named id which is primary key . Goal is that the rows should be sorted by id in ASC order, that’s why this query isn’t working
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What is the correct file extension for GLSL shaders? [closed]
...haders.
You can store the vertex shader and fragment shader content in a char * variable and compile, link and attach the shader to a program.
Another way is to write the seperate vertex and fragment shader file with whatever extension you like and read it to compile, link and attach the shader t...
How do I select an element with its name attribute in jQuery? [duplicate]
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$('[name="ElementNameHere"]').doStuff();
jQuery supports CSS3 style selectors, plus some more.
See more
jQuery - Selectors
jQuery - [attribute=""] selector
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How can I change IIS Express port for a site
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In Solution Explorer, right-click the name of the application and then select Properties.
Click the Web tab.
In the Servers section, under Use Local IIS Web server, in the Project URL box change the port number.
To the right of the Project URL box, click Create Virtual Directory, and then ...
'IF' in 'SELECT' statement - choose output value based on column values
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SELECT id,
IF(type = 'P', amount, amount * -1) as amount
FROM report
See http://dev.mysql.com/doc/refman/5.0/en/control-flow-functions.html.
Additionally, you could handle when the condition is null. In the case of...