大约有 9,000 项符合查询结果（耗时：0.0219秒） [XML]
What is a domain specific language? Anybody using it? And in what way?
... system figures out the how.
Examples of DSL include all query languages (SQL, XPath, ...), all template languages (Django, Smarty, ...), shell scripts, especially including stuff like twill, a command driven web browser (mostly used for automated test), data storage and exchange languages (XML, YA...
How do you run a single query through mysql from the command line?
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mysql -u <user> -p -e "select * from schema.table"
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Get top n records for each group of grouped results
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Here is one way to do this, using UNION ALL (See SQL Fiddle with Demo). This works with two groups, if you have more than two groups, then you would need to specify the group number and add queries for each group:
(
select *
from mytable
where `group` = 1
order by...
Interface or an Abstract Class: which one to use?
...umber;
public $DateHired;
public function write_info(){
//sql codes here
echo "Writing ". $this->LastName . "'s info to emloyee dbase table <br>";
}
}
final class student extends person{
public $StudentNumber;
public $CourseName;
public functio...
Is it Linq or Lambda?
... of my code is of the "LINQ to Objects" variety. But if you have a lot of SQL experience, perhaps query syntax will be easier to understand at first.
– Tom Bushell
Sep 12 '11 at 18:32
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Combining INSERT INTO and WITH/CTE
...a table (either regular, or temp).
WITH common_table_expression (Transact-SQL)
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Access Denied for User 'root'@'localhost' (using password: YES) - No Privileges?
...ng the root password, we'll going to forcefully INSERT a record into the mysql.user table
In the init file, use this instead
INSERT INTO mysql.user (Host, User, Password) VALUES ('%', 'root', password('YOURPASSWORD'));
GRANT ALL ON *.* TO 'root'@'%' WITH GRANT OPTION;
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Why does MYSQL higher LIMIT offset slow the query down?
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) q
JOIN mytable t
ON t.id = q.id
See this article:
MySQL ORDER BY / LIMIT performance: late row lookups
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LINQ query to select top five
...edited Apr 3 '15 at 11:34
csharpsql
1,49211 gold badge1313 silver badges2121 bronze badges
answered Sep 23 '14 at 7:02
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Primary key or Unique index?
...n it tries to insert the value 1 into this column for a second time.
In MySQL a unique constraint allows multiple NULLs.
It is possible to make a unique index on mutiple columns.
Primary key versus unique index
Things that are the same:
A primary key implies a unique index.
Things that are d...