大约有 40,000 项符合查询结果（耗时：0.0331秒） [XML]
Warning: Null value is eliminated by an aggregate or other SET operation in Aqua Data Studio
...t the solution specifically for the "opencases" column be simpler as just "select count(1)..." (or "count" of any other literal)? The Where clause already specifies "and closed is NULL" so no need for summing a case statement in this instance. Also, I've heard (aeons ago) that "count(*)" is not as e...
Calculate difference between two datetimes in MySQL
...
USE TIMESTAMPDIFF MySQL function. For example, you can use:
SELECT TIMESTAMPDIFF(SECOND, '2012-06-06 13:13:55', '2012-06-06 15:20:18')
In your case, the third parameter of TIMSTAMPDIFF function would be the current login time (NOW()). Second parameter would be the last login time, w...
MVC3 DropDownListFor - a simple example?
...uirements. Now, however, how is MVC FW supposed to map the value that is selected on this drop-down back into the simple string property on my view model?
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How to create json by JavaScript for loop?
I have array of select tag.
5 Answers
5
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How to insert text into the textarea at the current cursor position?
...ction insertAtCursor(myField, myValue) {
//IE support
if (document.selection) {
myField.focus();
sel = document.selection.createRange();
sel.text = myValue;
}
//MOZILLA and others
else if (myField.selectionStart || myField.selectionStart == '0') {
...
How do I check OS with a preprocessor directive?
...eturn a name of platform, if determined, otherwise - an empty string
const char *get_platform_name() {
return (PLATFORM_NAME == NULL) ? "" : PLATFORM_NAME;
}
int main(int argc, char *argv[]) {
puts(get_platform_name());
return 0;
}
Tested with GCC and clang on:
Debian 8
Windows (Min...
How do I modify fields inside the new PostgreSQL JSON datatype?
With postgresql 9.3 I can SELECT specific fields of a JSON data type, but how do you modify them using UPDATE? I can't find any examples of this in the postgresql documentation, or anywhere online. I have tried the obvious:
...
SQLite select where empty?
In SQLite, how can I select records where some_column is empty?
Empty counts as both NULL and "".
4 Answers
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SQL Joins Vs SQL Subqueries (Performance)?
...e result i was looking for was 739 elements.
My query at first was this:
SELECT p.id,
p.fixedId,
p.azienda_id,
p.categoria_id,
p.linea,
p.tipo,
p.nome
FROM prodotto p
WHERE p.azienda_id = 2699 AND p.anno = (
SELECT MAX(p2.anno)
FROM prodotto p2
WHERE p2.fixed...
What is the difference between sigaction and signal?
...s defined in the C standard. Nevertheless, it has a number of undesirable characteristics that sigaction() avoids - unless you use the flags explicitly added to sigaction() to allow it to faithfully simulate the old signal() behaviour.
The signal() function does not (necessarily) block other signa...