大约有 43,000 项符合查询结果（耗时：0.0535秒） [XML]
How can I suppress column header output for a single SQL statement?
...in batch (using the mysql command-line binary). I want one of my several SELECT statements to not print the column headers, just the selected records. Is this possible?
...
How do I get SUM function in MySQL to return '0' if no values are found?
...
Use COALESCE to avoid that outcome.
SELECT COALESCE(SUM(column),0)
FROM table
WHERE ...
To see it in action, please see this sql fiddle: http://www.sqlfiddle.com/#!2/d1542/3/0
More Information:
Given three tables (one with all numbers, one with all nul...
Where do “pure virtual function call” crashes come from?
...asily optimized away):
#include <iostream>
using namespace std;
char pool[256];
struct Base
{
virtual void foo() = 0;
virtual ~Base(){};
};
struct Derived: public Base
{
virtual void foo() override { cout <<"Derived::foo()" << endl;}
};
int main()
{
...
How to make connection to Postgres via Node.js
...values($1, $2)", ['John', x]);
x = x - 1;
}
var query = client.query("SELECT * FROM junk");
//fired after last row is emitted
query.on('row', function(row) {
console.log(row);
});
query.on('end', function() {
client.end();
});
//queries can be executed either via text/parameter val...
How do I see the current encoding of a file in Sublime Text?
...has no BOM (byte-order mark), (b) the file contains only single-byte ASCII chars., (c) the file has not yet been saved by Sublime Text in this session. Once saved by ST , it then reports 'UTF8' until closed (on re-opening the guessing starts over).
– mklement0
...
Selecting pandas column by location
...ed in future versions. See pandas.pydata.org/pandas-docs/dev/… on how to select by position using iloc/iat.
– Wouter Overmeire
Apr 12 '13 at 10:04
1
...
How to get the error message from the error code returned by GetLastError()?
...dated (11/2017) to take into consideration some comments.
Easy example:
wchar_t buf[256];
FormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
NULL, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
buf, (sizeof(buf) / sizeof(wchar_t)),...
How to generate a simple popup using jQuery
...
First the CSS - tweak this however you like:
a.selected {
background-color:#1F75CC;
color:white;
z-index:100;
}
.messagepop {
background-color:#FFFFFF;
border:1px solid #999999;
cursor:default;
display:none;
margin-top: 15px;
position:absolute;
text-a...
jQuery select all except first
In jQuery how do I use a selector to access all but the first of an element? So in the following code only the second and third element would be accessed. I know I can access them manually but there could be any number of elements so thats not possible. Thanks.
...
How do I use itertools.groupby()?
...string)]
will give you a list of 2-tuples where the first element is the char and the 2nd is the number of repetitions.
Edit: Note that this is what separates itertools.groupby from the SQL GROUP BY semantics: itertools doesn't (and in general can't) sort the iterator in advance, so groups with t...