大约有 34,900 项符合查询结果（耗时：0.0314秒） [XML]
How to find gaps in sequential numbering in mysql?
...performance.
The (not as fast as possible) answer
Here's version that works on table of any size (not just on 100 rows):
SELECT (t1.id + 1) as gap_starts_at,
(SELECT MIN(t3.id) -1 FROM arrc_vouchers t3 WHERE t3.id > t1.id) as gap_ends_at
FROM arrc_vouchers t1
WHERE NOT EXISTS (SELECT t...
How do I send an HTML email?
...
Dave Jarvis
27.6k3535 gold badges157157 silver badges281281 bronze badges
answered Feb 21 '11 at 17:06
BalusCBalusC
...
What is the difference between varchar and nvarchar?
...data. A varchar column is restricted to an 8-bit codepage. Some people think that varchar should be used because it takes up less space. I believe this is not the correct answer. Codepage incompatabilities are a pain, and Unicode is the cure for codepage problems. With cheap disk and memory nowadays...
Display Animated GIF
...ndroid.graphics.Movie class.
This is not too much documented, but is in SDK Reference. Moreover, it is used in Samples in ApiDemos in BitmapDecode example with some animated flag.
share
|
improve t...
Which HTML Parser is the best? [closed]
...st released a new Java HTML parser: jsoup. I mention it here because I think it will do what you are after.
Its party trick is a CSS selector syntax to find elements, e.g.:
String html = "<html><head><title>First parse</title></head>"
+ "<body><p>Parsed ...
What is LINQ and what does it do? [closed]
What is LINQ? I know it's for databases, but what does it do?
7 Answers
7
...
How do I determine if a port is open on a Windows server? [closed]
... that you're trying to use:
On the server itself, use netstat -an to check to see which ports are listening.
From outside, just use telnet host port (or telnet host:port on Unix systems) to see if the connection is refused, accepted, or timeouts.
On that latter test, then in general:
connectio...
What does “while True” mean in Python?
...
while True means loop forever. The while statement takes an expression and executes the loop body while the expression evaluates to (boolean) "true". True always evaluates to boolean "true" and thus executes the loop body indefinitely. It's an idiom that you'll just get used to...
Create a date from day month and year with T-SQL
...
Cade RouxCade Roux
82.1k3838 gold badges167167 silver badges258258 bronze badges
...
How do 20 questions AI algorithms work?
...
You can think of it as the Binary Search Algorithm.
In each iteration, we ask a question, which should eliminate roughly half of the possible word choices. If there are total of N words, then we can expect to get an answer after log2(N) ...