大约有 1,948 项符合查询结果（耗时：0.0125秒） [XML]
What are the use cases for selecting CHAR over VARCHAR in SQL?
...rchar, it's free to use 1-3 bytes per character as needed. This is in the MySQL manual: dev.mysql.com/doc/refman/5.0/en/charset-unicode-utf8.html
– Gavin Towey
Mar 27 '14 at 2:14
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How to select all records from one table that do not exist in another table?
...E b.Key IS NULL;
https://www.cloudways.com/blog/how-to-join-two-tables-mysql/
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ActiveRecord.find(array_of_ids), preserving order
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The answer is for mysql only
There is a function in mysql called FIELD()
Here is how you could use it in .find():
>> ids = [100, 1, 6]
=> [100, 1, 6]
>> WordDocument.find(ids).collect(&:id)
=> [1, 6, 100]
>> WordD...
Mac SQLite editor [closed]
I am aware of CocoaMySQL but I have not seen a Mac GUI for SQLite, is there one?
15 Answers
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What is Common Gateway Interface (CGI)?
...st for page ---> webserver ---[CGI]----> Server side Program ---> MySQL Server.
Most if not all, webservers can be configured to execute a program as a 'CGI'. This means that the webserver, upon receiving a request, will forward the data to a specific program, setting some environment vari...
Can the jQuery UI Datepicker be made to disable Saturdays and Sundays (and holidays)?
...file getdate.php
[php]
$sql="SELECT dates FROM holidaydates";
$result = mysql_query($sql);
$chkdate = $_POST['chkdate'];
$str='';
while($row = mysql_fetch_array($result))
{
$str .=$row[0].'';
}
echo $str;
[/php]
Happy Coding !!!! :-)
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Conveniently map between enum and int / String
...I always store constants as strings in my databases. (Actually, when using MySql, I store them as MySql enums!)
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How to use index in select statement?
...swer your specific question you have to specify the DB you are using.
For MySQL, you want to read the Index Hint Syntax documentation on how to do this
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What is the difference between JOIN and UNION?
... subsets it -- completely different operations. Trivial example of UNION:
mysql> SELECT 23 AS bah
-> UNION
-> SELECT 45 AS bah;
+-----+
| bah |
+-----+
| 23 |
| 45 |
+-----+
2 rows in set (0.00 sec)
similary trivial example of JOIN:
mysql> SELECT * FROM
-> (SELECT...
Do I need to create indexes on foreign keys on Oracle?
...int creates also an index... i.e. Jet Engine (MSAccess files, Firebird and MySQL)
– bubi
Apr 23 '15 at 15:19
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