大约有 42,000 项符合查询结果（耗时：0.0367秒） [XML]
How do I delete a fixed number of rows with sorting in PostgreSQL?
...
You could try using the ctid:
DELETE FROM logtable
WHERE ctid IN (
SELECT ctid
FROM logtable
ORDER BY timestamp
LIMIT 10
)
The ctid is:
The physical location of the row version within its table. Note that although the ctid can b...
Create dynamic URLs in Flask with url_for()
...lot o stuff with it, for example:
@app.route('/questions/<int:question_id>'): #int has been used as a filter that only integer will be passed in the url otherwise it will give a 404 error
def find_question(question_id):
return ('you asked for question{0}'.format(question_id))
For t...
Insert Update stored proc on SQL Server
...re the check for existence
should only be done when there is a
very valid reason to justify the
additional I/O. The optimized way to
do things is to make sure that you
have little reads as possible on the
DB.
The best strategy is to attempt the
update. If no rows are affected by t...
COUNT(*) vs. COUNT(1) vs. COUNT(pk): which is better? [duplicate]
...ies that need to count everything, even for joins, use *
SELECT boss.boss_id, COUNT(subordinate.*)
FROM boss
LEFT JOIN subordinate on subordinate.boss_id = boss.boss_id
GROUP BY boss.id
But don't use COUNT(*) for LEFT joins, as that will return 1 even if the subordinate table doesn't match anythi...
Correct way to pass multiple values for same parameter name in GET request
...ost applications use the first option you have shown: http://server/action?id=a&id=b. To support that information, take a look at this Stackoverflow link, and this MSDN link regarding ASP.NET applications, which use the same standard for parameters with multiple values.
However, since you are d...
When should I use cross apply over inner join?
... (
SELECT TOP 3 *
FROM t2
WHERE t2.t1_id = t1.id
ORDER BY
t2.rank DESC
) t2o
It cannot be easily formulated with an INNER JOIN condition.
You could probably do something like that using CTE's and window function:
WITH t2o AS...
Get specific object by id from array of objects in AngularJS
...s to get only one object from the array. So I d like for example Item with id 1.
17 Answers
...
Check if a key exists inside a json object
...bove is the JSON object I'm dealing with. I want to check if the 'merchant_id' key exists. I tried the below code, but it's not working. Any way to achieve it?
...
MySql Table Insert if not exist otherwise update
.... (Bug #11765650, Bug #58637) Bug 58637 description bugs.mysql.com/bug.php?id=58637
– broadband
Sep 2 '14 at 13:28
...
Binding a WPF ComboBox to a custom list
...hemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="300" Width="300">
<Grid>
<StackPanel>
<Button Click="Button_Click">asdf</Button>
<ComboBox ItemsSource="{Binding Path=PhonebookEntries}"
DisplayMemberPath="Name"
...