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MySQL: how to get the difference between two timestamps in seconds
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You could use the TIMEDIFF() and the TIME_TO_SEC() functions as follows:
SELECT TIME_TO_SEC(TIMEDIFF('2010-08-20 12:01:00', '2010-08-20 12:00:00')) diff;
+------+
| diff |
+------+
| 60 |
+------+
1 row in set (0.00 sec)
You could also use the UNIX_TIMESTAMP() function as @Amber suggested in a...
How to print SQL statement in codeigniter model
...veRecord generated SQL:
Before the query runs:
$this->db->_compile_select();
And after it has run:
$this->db->last_query();
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How to combine two or more querysets in a Django view?
...s. For example:
>>> qs1.union(qs2, qs3)
The UNION operator selects only distinct values by default. To allow duplicate values, use the all=True
argument.
union(), intersection(), and difference() return model instances of
the type of the first QuerySet even if the arguments ...
Check if a value exists in pandas dataframe index
...ues or the index by appending the ".values" method, e.g.
g in df.<your selected field>.values
g in df.index.values
I find that adding the ".values" to get a simple list or ndarray out makes exist or "in" checks run more smoothly with the other python tools. Just thought I'd toss that out th...
How can I remove the first line of a text file using bash/sed script?
... of magnitude. I'm testing it on a file of 500,000K lines (no more than 50 chars per line). However, I then realized I was using the FreeBSD version of tail (which comes with OS X by default). When I switched to GNU tail, the tail call was 10 times faster than the sed call (and the GNU sed call, too...
Excel “External table is not in the expected format.”
...e same problem. which as resolved using these steps:
1.) Click File
2.) Select "save as"
3.) Click on drop down (Save as type)
4.) Select Excel 97-2003 Workbook
5.) Click on Save button
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How to zero pad a sequence of integers in bash so that all have the same width?
...e small correction: strictly speaking, seq supports a subset of the format chars. that printf supports (and that subsets includes g, but not d). The behavior of characters d and g differs subtly in that d interprets 0-prefixed numbers strings as octal numbers and converts them to decimal, whereas g ...
mysql - how many columns is too many?
...every column to be returned by every query is perfectly normal; that's why SELECT statement lets you explicitly name the columns you need.
As a general rule, your table structure should reflect your domain model; if you really do have 70 (100, what have you) attributes that belong to the same entit...
In Xcode, how to suppress all warnings in specific source files?
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Select your target and show Build Phases. Then enter the name of the file in the search box, and you should see it listed in the Compile Sources phase. Double-click in the Compiler Flags column for that file and enter -w to t...
Consistency of hashCode() on a Java string
....x the hashCode
function for long Strings worked by
sampling every nth character. This
pretty well guaranteed you would have
many Strings hashing to the same
value, thus slowing down Hashtable
lookup. In JDK 1.2 the function has
been improved to multiply the result
so far by 31 then ...