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Finding duplicate values in a SQL table
...ly group on both of the columns.
Note: the older ANSI standard is to have all non-aggregated columns in the GROUP BY but this has changed with the idea of "functional dependency":
In relational database theory, a functional dependency is a constraint between two sets of attributes in a relation...
What is the difference between a string and a byte string?
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@orety they do have to be encoded somehow internally for exactly that reason, but this isn't expos3s to you from Python code much like you don't have to care about how floating point numbers are stored.
– lvc
Nov 5 '17 at 22:43
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How are the points in CSS specificity calculated
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Pekka's answer is practically correct, and probably the best way to think about the issue.
However, as many have already pointed out, the W3C CSS recommendation states that "Concatenating the three numbers a-b-c (in a number system with a large base...
How to Right-align flex item?
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Thanks. Would you personally prefer this over Yohann Tilotti's display table method above? If so, why?
– Mark Boulder
Mar 16 '14 at 4:19
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How do PHP sessions work? (not “how are they used?”)
...on files are usually stored in, say, /tmp/ on the server, and named sess_{session_id} . I have been looking at the contents and cannot figure out how they really work.
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jQuery: select an element's class and id at the same time?
... yes you can specify a selector that has to match ID and class (and potentially tag name and anything else you want to throw in).
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Why isn't vector a STL container?
... avoid vector <bool> as it's not an STL container and it doesn't really hold bool s.
6 Answers
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Sorting multiple keys with Unix sort
I have potentially large files that need to be sorted by 1-n keys. Some of these keys might be numeric and some of them might not be. This is a fixed-width columnar file so there are no delimiters.
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Rebase array keys after unsetting elements
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@webbiedave sorry, but that is not true. It does actually reorder my array. Very very strange.
– FooBar
Jun 23 '14 at 16:28
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How do I get bit-by-bit data from an integer value in C?
...ude <stdlib.h>
int *get_bits(int n, int bitswanted){
int *bits = malloc(sizeof(int) * bitswanted);
int k;
for(k=0; k<bitswanted; k++){
int mask = 1 << k;
int masked_n = n & mask;
int thebit = masked_n >> k;
bits[k] = thebit;
}
return bits;
}
in...