大约有 40,000 项符合查询结果（耗时：0.0319秒） [XML]
How do I (or can I) SELECT DISTINCT on multiple columns?
...INCT a,b,c FROM t
is roughly equivalent to:
SELECT a,b,c FROM t GROUP BY a,b,c
It's a good idea to get used to the GROUP BY syntax, as it's more powerful.
For your query, I'd do it like this:
UPDATE sales
SET status='ACTIVE'
WHERE id IN
(
SELECT id
FROM sales S
INNER JOIN
...
How to convert a Django QuerySet to a list
...
By the use of slice operator with step parameter which would cause evaluation of the queryset and create a list.
list_of_answers = answers[::1]
or initially you could have done:
answers = Answer.objects.filter(id__in=[ans...
On Duplicate Key Update same as insert
... the unique key.
Someone else suggested before you can reduce some typing by doing:
INSERT INTO `tableName` (`a`,`b`,`c`) VALUES (1,2,3)
ON DUPLICATE KEY UPDATE `a`=VALUES(`a`), `b`=VALUES(`b`), `c`=VALUES(`c`);
share
...
SQL Add foreign key to existing column
...
Looks like whichever column is referenced by FK__Employees__UserI__04E4BC85 is not defined as PRIMARY KEY or candidate key in ActiveDirectories table.
– BluesRockAddict
Apr 30 '12 at 20:09
...
HTML.ActionLink vs Url.Action in ASP.NET Razor
... point which I like is using Url.Action(...)
You are creating anchor tag by your own where you can set your own linked text easily even with some other html tag.
<a href="@Url.Action("actionName", "controllerName", new { id = "<id>" })">
<img src="<ImageUrl>" style"width:...
Android: View.setID(int id) programmatically - how to avoid ID conflicts?
... Interesting, I wasn't aware that IDs need not be unique? So does findViewById make any guarantees then as to which view is returned if there's more than one with the same ID? The docs don't mention anything.
– Matthias
May 3 '12 at 10:04
...
jQuery - checkbox enable/disable
...on is not available, so you need to use .attr().
To disable the checkbox (by setting the value of the disabled attribute) do
$("input.group1").attr('disabled','disabled');
and for enabling (by removing the attribute entirely) do
$("input.group1").removeAttr('disabled');
Any version of jQuery
...
How to put Google Maps V2 on a Fragment using ViewPager
...
By using this code we can setup MapView anywhere, inside any ViewPager or Fragment or Activity.
In the latest update of Google for Maps, only MapView is supported for fragments. MapFragment & SupportMapFragment doesn't w...
Alter MySQL table to add comments on columns
...s you from accidentally losing an important part of your column definition by not realising that you need to include it in your MODIFY or CHANGE clause. For example, if you MODIFY an AUTO_INCREMENT column, you need to explicitly specify the AUTO_INCREMENT modifier again in the MODIFY clause, or the ...
How to do SELECT COUNT(*) GROUP BY and ORDER BY in Django?
...saction.objects.all().values('actor').annotate(total=Count('actor')).order_by('total')
values() : specifies which columns are going to be used to "group by"
Django docs:
"When a values() clause is used to constrain the columns that are
returned in the result set, the method for evaluating annotati...