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Update multiple rows in same query using PostgreSQL
...izable:
update test as t set
column_a = c.column_a
from (values
('123', 1),
('345', 2)
) as c(column_b, column_a)
where c.column_b = t.column_b;
You can add as many columns as you like:
update test as t set
column_a = c.column_a,
column_c = c.column_c
from (values
('12...
What is the difference between LL and LR parsing?
...back to some nonterminal by reversing a production.
As an example, an LR(1) parser (with one token of lookahead) might parse that same string as follows:
Workspace Input Action
---------------------------------------------------------
int + int + int Shift
...
Which terminal command to get just IP address and nothing else?
...
181
You can write a script that only return the IP like:
/sbin/ifconfig eth0 | grep 'inet addr' |...
Undefined behavior and sequence points
... C++03
This answer is for the older versions of the C++ standard. The C++11 and C++14 versions of the standard do not formally contain 'sequence points'; operations are 'sequenced before' or 'unsequenced' or 'indeterminately sequenced' instead. The net effect is essentially the same, but the term...
What are the complexity guarantees of the standard containers?
...; Make an empty vector. O(1)
vector<T> v(n); Make a vector with N elements. O(n)
vector<T> v(n, value); Make a vector with N elements, initialized to value. O(n)
vector<T> v(begin, end); ...
How to read/write a boolean when implementing the Parcelable interface?
...
12 Answers
12
Active
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How to convert a string of numbers to an array of numbers?
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14 Answers
14
Active
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Why does 'continue' behave like 'break' in a Foreach-Object?
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165
Simply use the return instead of the continue. This return returns from the script block which...
CommandError: You must set settings.ALLOWED_HOSTS if DEBUG is False
I use Django 1.6.5 in my program txsite with the settings:
8 Answers
8
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