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mkdir -p functionality in Python [duplicate]
...rs will fail, in all multitasking operating systems. It's like saying "256 chars should be enough for any path created".
– tzot
Mar 2 '09 at 23:42
4
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How can I select rows with most recent timestamp for each key value?
...r data. Each row has a sensor id, a timestamp, and other fields. I want to select a single row with latest timestamp for each sensor, including some of the other fields.
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how to listen to N channels? (dynamic select statement)
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You can do this using the Select function from the reflect package:
func Select(cases []SelectCase) (chosen int, recv Value, recvOK bool)
Select executes a select operation described by the list of cases. Like
the Go select statement, it bl...
Windbg Step 2 分析程序堆栈实战 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...转载+整理http: www.cnblogs.com killmyday#include"stdafx.h"#include<tchar.h>#ifdef_UNICODE#define_ttol_wtol#else#define_ttolatol#e...转载+整理 http://www.cnblogs.com/killmyday
#include "stdafx.h"
#include <tchar.h>
#ifdef _UNICODE
#define _ttol _wtol
#else
#define _ttol atol
#...
SQL query to find record with ID not in another table
...
Try this
SELECT ID, Name
FROM Table1
WHERE ID NOT IN (SELECT ID FROM Table2)
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What is the fastest factorial function in JavaScript? [closed]
...n fac(n){
return(n<2)?1:fac(n-1)*n;
}
It's the simplest way (less characters / lines) I've found, only a function with one code line.
Edit:
If you really want to save some chars you can go with an Arrow Function (21 bytes):
f=n=>(n<2)?1:f(n-1)*n
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Count number of records returned by group by
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You can do both in one query using the OVER clause on another COUNT
select
count(*) RecordsPerGroup,
COUNT(*) OVER () AS TotalRecords
from temptable
group by column_1, column_2, column_3, column_4
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must appear in the GROUP BY clause or be used in an aggregate function
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Yes, this is a common aggregation problem. Before SQL3 (1999), the selected fields must appear in the GROUP BY clause[*].
To workaround this issue, you must calculate the aggregate in a sub-query and then join it with itself to get the additional columns you'd need to show:
SELECT m.cname...
java.sql.SQLException: Incorrect string value: '\xF0\x9F\x91\xBD\xF0\x9F…'
...e basic multilingual plane. They cannot be even represented in java as one char, "????????".length() == 4. They are definitely not null characters and one will see squares if you are not using fonts that support them.
MySQL's utf8 only supports basic multilingual plane, and you need to use utf8mb4 ...
How do I check to see if a value is an integer in MySQL?
...e REGEXP operator, matching the string to a regular expression. Simply do
select field from table where field REGEXP '^-?[0-9]+$';
this is reasonably fast. If your field is numeric, just test for
ceil(field) = field
instead.
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