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Difference between natural join and inner join
...t specify the joining columns in a natural join; the join is strictly name-based. See also Wikipedia.)
(There's a cheat in the inner join output; the a. and b. parts would not be in the column names; you'd just have column1, column2, column1, column3 as the headings.)
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Rails 4 Authenticity Token
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For my Rails 4.0.8 based App it was enough to write =token_tag nil or (in .erb) <%= token_tag nil %>
– jmarceli
Nov 10 '14 at 20:40
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Frontend tool to manage H2 database [closed]
How to use H2 database 's integrated managment frontend?
10 Answers
10
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Vim users, where do you rest your right hand? [closed]
...en make 3rd & 4th fingers left & right
Then, to avoid overwriting base Vim features: Toss whatever used to be on ; to the now-empty h button
As a cute bonus, the "l" key now stands for "left" ;)
noremap l h
noremap ; l
noremap h ;
The previous "runners-up", who both u...
How to select the rows with maximum values in each group with dplyr? [duplicate]
...py the count table into a new object. Then filter for the max of the group based on the first grouping characteristic. For example:
count_table <- df %>%
group_by(A, B) %>%
count() %>%
arrange(A, desc(n))
count_table %>%
group_by...
How can I efficiently select a Standard Library container in C++11?
...arch tag.
Ordering
If you need a container of items to always be sorted based on a particular comparison operation, you can use a set. Or a multi_set if you need multiple items to have the same value.
Or you can use a sorted std::vector, but you'll have to keep it sorted.
Stability
When iterat...
Java `final` method: what does it promise?
...You can't override it in your derived class, therefore it will do what the base class author intended.
http://download.oracle.com/javase/tutorial/java/IandI/final.html
Worth noting is the part where it suggests that methods called from constructors should be final.
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What is the purpose of Order By 1 in SQL select statement?
...RDER BY 1
...is known as an "Ordinal" - the number stands for the column based on the number of columns defined in the SELECT clause. In the query you provided, it means:
ORDER BY A.PAYMENT_DATE
It's not a recommended practice, because:
It's not obvious/explicit
If the column order changes, ...
Linq to Entities join vs groupjoin
... input sequence, found all the matching items from the "inner" sequence
(based on a key projection on each sequence) and then yielded pairs of
matching elements. GroupJoin is similar, except that instead of
yielding pairs of elements, it yields a single result for each "outer"
item based on ...
Storing time-series data, relational or non?
...n is never a Key (duplicate rows, which are prohibited in a Relational database, must be prevented by other means).
The Id column requires an additional Index, which obviously impedes the speed of INSERT/DELETE, and adds to the disk space used.
You can get rid of it. Please.
Elevation
Now ...