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What is the fastest factorial function in JavaScript? [closed]
...n fac(n){
return(n<2)?1:fac(n-1)*n;
}
It's the simplest way (less characters / lines) I've found, only a function with one code line.
Edit:
If you really want to save some chars you can go with an Arrow Function (21 bytes):
f=n=>(n<2)?1:f(n-1)*n
...
How do I check to see if a value is an integer in MySQL?
...e REGEXP operator, matching the string to a regular expression. Simply do
select field from table where field REGEXP '^-?[0-9]+$';
this is reasonably fast. If your field is numeric, just test for
ceil(field) = field
instead.
...
How to concatenate text from multiple rows into a single text string in SQL server?
...y, John, Sam
2 Alaina, Edward
I used the following T-SQL:
SELECT Main.SubjectID,
LEFT(Main.Students,Len(Main.Students)-1) As "Students"
FROM
(
SELECT DISTINCT ST2.SubjectID,
(
SELECT ST1.StudentName + ',' AS [text()]
FR...
How do I perform an IF…THEN in an SQL SELECT?
How do I perform an IF...THEN in an SQL SELECT statement?
30 Answers
30
...
java.sql.SQLException: Incorrect string value: '\xF0\x9F\x91\xBD\xF0\x9F…'
...e basic multilingual plane. They cannot be even represented in java as one char, "????????".length() == 4. They are definitely not null characters and one will see squares if you are not using fonts that support them.
MySQL's utf8 only supports basic multilingual plane, and you need to use utf8mb4 ...
Create a temporary table in a SELECT statement without a separate CREATE TABLE
Is it possible to create a temporary (session only) table from a select statement without using a create table statement and specifying each column type? I know derived tables are capable of this, but those are super-temporary (statement-only) and I want to re-use.
...
Using LIMIT within GROUP BY to get N results per group?
...to get all years into a single column, grouped by id and ordered by rate:
SELECT id, GROUP_CONCAT(year ORDER BY rate DESC) grouped_year
FROM yourtable
GROUP BY id
Result:
-----------------------------------------------------------
| ID | GROUPED_YEAR |...
Simplest way to do a recursive self-join?
...
WITH q AS
(
SELECT *
FROM mytable
WHERE ParentID IS NULL -- this condition defines the ultimate ancestors in your chain, change it as appropriate
UNION ALL
SELECT m.*
FROM mytable m
...
Is there any difference between GROUP BY and DISTINCT
...CT and distinct by UNION cause an oracle error, but GROUP BY worked; I was selecting only 1 column from a view and not using any aggregation; I'm still baffled why it required it, but it does confirm there is some difference in the execution. As others point out, it also lets you GROUP BY columns no...
What's the difference between KeyDown and KeyPress in .NET?
...ctical difference between KeyDown and KeyPress is that KeyPress relays the character resulting from a keypress, and is only called if there is one.
In other words, if you press A on your keyboard, you'll get this sequence of events:
KeyDown: KeyCode=Keys.A, KeyData=Keys.A, Modifiers=Keys.None
Key...