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How to select all records from one table that do not exist in another table?
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SELECT t1.name
FROM table1 t1
LEFT JOIN table2 t2 ON t2.name = t1.name
WHERE t2.name IS NULL
Q: What is happening here?
A: Conceptually, we select all rows from table1 and for each row we attempt to find a row in table2 with the same ...
Convert a list of characters into a string
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Use the join method of the empty string to join all of the strings together with the empty string in between, like so:
>>> a = ['a', 'b', 'c', 'd']
>>> ''.join(a)
'abcd'
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How to use DISTINCT and ORDER BY in same SELECT statement?
After executing the following statement:
12 Answers
12
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Do the JSON keys have to be surrounded by quotes?
...rks. This is to make it simpler and to avoid having to have another escape method for javascript reserved keywords, ie {for:"foo"}.
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maximum value of int
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In C++:
#include <limits>
then use
int imin = std::numeric_limits<int>::min(); // minimum value
int imax = std::numeric_limits<int>::max();
std::numeric_limits is a template type which can be instantiated with other types:
float fmin = std::numeric_limits<floa...
Can you center a Button in RelativeLayout?
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android:layout_centerHorizontal="true"
Exactly like this, it works for me:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#ff...
Difference between View and table in sql
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A table contains data, a view is just a SELECT statement which has been saved in the database (more or less, depending on your database).
The advantage of a view is that it can join data from several tables thus creating a new view of it. Say you have a database with salaries...
How do you prevent install of “devDependencies” NPM modules for Node.js (package.json)?
... along other dependencies when run inside a package directory, in a development environment (the default).
Use npm install --only=prod (or --only=production) to install only dependencies, and not devDependencies,regardless of the value of the NODE_ENV environment variable.
Source: npm docs
Note: ...
Hide text using css
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long titles will have an issue with this method since only the text before word-wrap is indented, and the W3C spec doesn't specify a situation for negative indent so this could have unpredictable results
– Chris Farmiloe
Jan 23...
Aborting a shell script if any command returns a non-zero value?
...the beginning of the script:
set -e
This will cause the shell to exit immediately if a simple command exits with a nonzero exit value. A simple command is any command not part of an if, while, or until test, or part of an && or || list.
See the bash(1) man page on the "set" internal com...