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Efficient SQL test query or validation query that will work across all (or most) databases
...er a little bit of research along with help from some of the answers here:
SELECT 1
H2
MySQL
Microsoft SQL Server (according to NimChimpsky)
PostgreSQL
SQLite
SELECT 1 FROM DUAL
Oracle
SELECT 1 FROM any_existing_table WHERE 1=0
or
SELECT 1 FROM INFORMATION_SCHEMA.SYSTEM_USERS
or
CALL NOW()
HS...
Is there a JSON equivalent of XQuery/XPath?
...g
tools including filtering, recursive search, sorting, mapping, range
selection, and flexible expressions with wildcard string comparisons
and various operators.
JSONselect has another point of view on the question (CSS selector-like, rather than XPath) and has a JavaScript implementation.
...
select、poll、epoll之间的区别总结[整理] - C/C++ - 清泛网 - 专注C/C++及内核技术
select、poll、epoll之间的区别总结[整理]select，poll，epoll都是IO多路复用的机制。I O多路复用就通过一种机制，可以监视多个描述符，一旦某个描述符就绪（一般是读就绪或者写就绪...select，poll，epoll都是IO多路复用的机制。I/O多路...
Traits vs. interfaces
... example of a trait. to_integer would be more likely included in an IntegerCast interface because there is no fundamentally similar way to (intelligently) cast classes to an integer.
– Matthew
Feb 9 '12 at 4:13
...
The maximum recursion 100 has been exhausted before statement completion
...@EntDt = '12/31/2009';
declare @dcnt int;
;with DateList as
(
select @STARTDATE DateValue
union all
select DateValue + 1 from DateList
where DateValue + 1 < convert(VARCHAR(15),@EntDt,101)
)
select count(*) as DayCnt from (
select DateValue,...
MySQL, better to insert NULL or empty string?
...or an empty string using a bound variable but not for a NULL. This query:
SELECT *
FROM mytable
WHERE mytext = ?
will never match a NULL in mytext, whatever value you pass from the client. To match NULLs, you'll have to use other query:
SELECT *
FROM mytable
WHERE mytext IS NULL
...
Getting value of select (dropdown) before change
The thing I want to achieve is whenever the <select> dropdown is changed I want the value of the dropdown before change. I am using 1.3.2 version of jQuery and using on change event but the value I am getting over there is after change.
...
Why is setTimeout(fn, 0) sometimes useful?
... recently run into a rather nasty bug, wherein the code was loading a <select> dynamically via JavaScript. This dynamically loaded <select> had a pre-selected value. In IE6, we already had code to fix the selected <option> , because sometimes the <select> 's selected...
How to hide a in a menu with CSS?
...hat Chrome, it seems, will not allow me to hide <option> in a <select> . Firefox will.
13 Answers
...
How do I select text nodes with jQuery?
...ext nodes with the accepted filter function. If you're only interested in selecting text nodes that contain non-whitespace, try adding a nodeValue conditional to your filter function, like a simple $.trim(this.nodevalue) !== '':
$('element')
.contents()
.filter(function(){
return t...