大约有 44,000 项符合查询结果（耗时：0.0423秒） [XML]
Hash Map in Python
...] * self.size
def _get_hash(self, key):
hash = 0
for char in str(key):
hash += ord(char)
return hash % self.size
def add(self, key, value):
key_hash = self._get_hash(key)
key_value = [key, value]
if self.map[key_hash] is None:
...
MySQL: Fastest way to count number of rows
...s.
The solution is SQL_CALC_FOUND_ROWS. This is usually used when you are selecting rows but still need to know the total row count (for example, for paging).
When you select data rows, just append the SQL_CALC_FOUND_ROWS keyword after SELECT:
SELECT SQL_CALC_FOUND_ROWS [needed fields or *] FROM t...
TINYTEXT, TEXT, MEDIUMTEXT, and LONGTEXT maximum storage sizes
...ONGTEXT | 4,294,967,295 (232−1) bytes = 4 GiB
Note that the number of characters that can be stored in your column will depend on the character encoding.
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Case insensitive 'Contains(string)'
...y, which is language dependent. For example, the English language uses the characters I and i for the upper and lower case versions of the ninth letter, whereas the Turkish language uses these characters for the eleventh and twelfth letters of its 29 letter-long alphabet. The Turkish upper case vers...
Return positions of a regex match() in Javascript?
Is there a way to retrieve the (starting) character positions inside a string of the results of a regex match() in Javascript?
...
Condition within JOIN or WHERE
...of filtering criteria more easily maintainable.
For example, instead of:
SELECT *
FROM Customers c
INNER JOIN CustomerAccounts ca
ON ca.CustomerID = c.CustomerID
AND c.State = 'NY'
INNER JOIN Accounts a
ON ca.AccountID = a.AccountID
AND a.Status = 1
Write:
SELECT *
FROM Customer...
Is it possible to use the SELECT INTO clause with UNION [ALL]?
...
This works in SQL Server:
SELECT * INTO tmpFerdeen FROM (
SELECT top 100 *
FROM Customers
UNION All
SELECT top 100 *
FROM CustomerEurope
UNION All
SELECT top 100 *
FROM CustomerAsia
UNION All
SELECT top 100 *
FROM CustomerAme...
Best way to check if a URL is valid
...CII URLs to be valid; internationalized domain names (containing non-ASCII characters) will fail.
Example:
if (filter_var($url, FILTER_VALIDATE_URL) === FALSE) {
die('Not a valid URL');
}
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How do I map lists of nested objects with Dapper
... probably work:
Grab the courses:
var courses = cnn.Query<Course>("select * from Courses where Category = 1 Order by CreationDate");
Grab the relevant mapping:
var mappings = cnn.Query<CourseLocation>(
"select * from CourseLocations where CourseId in @Ids",
new {Ids = course...
How to get Last record from Sqlite?
...
Try this:
SELECT *
FROM TABLE
WHERE ID = (SELECT MAX(ID) FROM TABLE);
OR
you can also used following solution:
SELECT * FROM tablename ORDER BY column DESC LIMIT 1;
...