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Which is faster/best? SELECT * or SELECT column1, colum2, column3, etc
I've heard that SELECT * is generally bad practice to use when writing SQL commands because it is more efficient to SELECT columns you specifically need.
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Selecting with complex criteria from pandas.DataFrame
...se pandas it has some built in functions for comparison. So if you want to select values of "A" that are met by the conditions of "B" and "C" (assuming you want back a DataFrame pandas object)
df[['A']][df.B.gt(50) & df.C.ne(900)]
df[['A']] will give you back column A in DataFrame format.
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Want to find records with no associated records in Rails
... get everyone with no friends in the first case:
Person.where('id NOT IN (SELECT DISTINCT(person_id) FROM friends)')
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How to get the max of two values in MySQL?
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Use GREATEST()
E.g.:
SELECT GREATEST(2,1);
Note: Whenever if any single value contains null at that time this function always returns null (Thanks to user @sanghavi7)
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Clicking the text to select corresponding radio button
...t; and has 4 possible choices, using radio buttons to allow the user to select his/her answer. The current HTML for a single question looks like:
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How to convert a selection to lowercase or uppercase in Sublime Text
I have several strings selected in a file in Sublime Text and I want to convert them all to lowercase.
5 Answers
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Correct way to add external jars (lib/*.jar) to an IntelliJ IDEA project
...ps for adding external jars in IntelliJ IDEA:
Click File from the toolbar
Select Project Structure option (CTRL + SHIFT + ALT + S on Windows/Linux, ⌘ + ; on Mac OS X)
Select Modules at the left panel
Select Dependencies tab
Select + icon
Select 1 JARs or directories option
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Select unique or distinct values from a list in UNIX shell script
I have a ksh script that returns a long list of values, newline separated, and I want to see only the unique/distinct values. It is possible to do this?
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Select first 4 rows of a data.frame in R
How can I select the first 4 rows of a data.frame :
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MySQL: Transactions vs Locking Tables
...ransactions vs locking tables to ensure database integrity and make sure a SELECT and UPDATE remain in sync and no other connection interferes with it. I need to:
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