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How do I find a “gap” in running counter with SQL?
... FROM mytable mi
WHERE mi.id = mo.id + 1
)
ORDER BY
id
LIMIT 1
In SQL Server:
SELECT TOP 1
id + 1
FROM mytable mo
WHERE NOT EXISTS
(
SELECT NULL
FROM mytable mi
WHERE mi.id = mo.id + 1
)
ORDER BY
...
Why do people say there is modulo bias when using a random number generator?
...ay RAND_MAX is 10 and I decide to generate a random number between 0 and 2 by calling rand()%3. However, rand()%3 does not produce the numbers between 0 and 2 with equal probability!
When rand() returns 0, 3, 6, or 9, rand()%3 == 0. Therefore, P(0) = 4/11
When rand() returns 1, 4, 7, or 10, rand(...
What's the difference between a continuation and a callback?
...ed as a simple goto (with the stack frame of the calling function replaced by the stack frame of the tail call).
Bonus: Proceeding to continuation passing style. Consider the following program:
console.log(pythagoras(3, 4));
function pythagoras(x, y) {
return x * x + y * y;
}
N...
With MySQL, how can I generate a column containing the record index in a table?
...
You can also initialize @curRow by replacing the JOIN statement with a comma, like this: FROM league_girl l, (SELECT @curRow := 0) r
– Mike
Jun 27 '10 at 14:12
...
Differences between Proxy and Decorator Pattern
...icts the client. Decorator does not. Proxy may restrict what a client does by controlling access to functionality; or it may restrict what a client knows by performing actions that are invisible and unknown to the client. Decorator does the opposite: it enhances what its delegate does in a way that ...
Python integer division yields float
...wered Aug 15 '09 at 21:50
Jonas ByströmJonas Byström
21k2121 gold badges8383 silver badges132132 bronze badges
...
Why did my Git repo enter a detached HEAD state?
... 9fc9555312 Merge branch 'cc/shared-index-permbits'
it cannot detached by mistake a remote tracking branch
See:
C:\Users\vonc\arepo>git checkout origin/master
Note: switching to 'origin/master'.
You are in 'detached HEAD' state. You can look around, make experimental
changes and commit th...
How does a hash table work?
...entioned, is called a hash algorithm or hash computation and usually works by taking the data fed into it (the title of the book in this case) and calculates a number from it.
For simplicity, let's say that it just converts each letter and symbol into a number and sums them all up. In reality, it's...
What does it mean to “program to an interface”?
...ce, but beyond that I finally understood their use as a language construct by thinking of them as a means of classifying common traits or behaviors that were exhibited by potentially many non-related classes of objects.
For example -- say you have a SIM game and have the following classes:
class H...
Which iOS app version/build number(s) MUST be incremented upon App Store release?
...e you have your Version Number and Build Number set properly will help you by avoiding having your App automatically rejected for having them improperly configured.
For each new version of your App, you need to invent a new Version Number. This number should be a greater value than the last ...