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How can I SELECT rows with MAX(Column value), DISTINCT by another column in SQL?
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The fastest MySQL solution, without inner queries and without GROUP BY:
SELECT m.* -- get the row that contains the max value
FROM topten m -- "m" from "max"
LEFT JOIN topten b -- "b" from "...
How can I get the SQL of a PreparedStatement?
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This also depends on the implementation. In MySQL -- at least the version I was using a few years ago -- the JDBC driver actually built a conventional SQL query from the template and bind variables. I guess that version of MySQL didn't support prepared statements nativ...
Upgrading PHP in XAMPP for Windows?
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Take a backup of your htdocs and data folder (subfolder of MySQL folder), reinstall upgraded version and replace those folders.
Note:
In case you have changed config files like PHP (php.ini), Apache (httpd.conf) or any other, please take back up of those files as well and replace th...
MQTT与TCP的区别 - 创客硬件开发 - 清泛IT社区，为创新赋能！
... Maori dictionary)。10. mqtt客户端connect时，可以带有用户名和密码，用于验证客户端。服务端可以根据clientid、IP地址、用户名等进行ACL访问控制。可以通过自定义应用消息实现客户端对服务端的身份验证。11. 有商业和开源的mqtt broke...
How to check if field is null or empty in MySQL?
...uld like to check in PHP , then you should do something like :
$query_s =mysql_query("SELECT YOURROWNAME from `YOURTABLENAME` where name = $name");
$ertom=mysql_fetch_array($query_s);
if ('' !== $ertom['YOURROWNAME']) {
//do your action
echo "It was filled";
} else {
echo "it was empty!";
}...
Get top n records for each group of grouped results
...g this: The version is the variables is close to being correct. However, MySQL does not guarantee the order of evaluation of expressions in the SELECT (and, in fact, sometimes evaluates them out-of-order). The key to the solution is to put all the variable assignments in a single expression; here...
MySQL JOIN the most recent row only?
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For anyone who must work with an older version of MySQL (pre-5.0 ish) you are unable to do sub-queries for this type of query. Here is the solution I was able to do and it seemed to work great.
SELECT MAX(d.id), d2.*, CONCAT(title,' ',forename,' ',surname) AS name
FROM cust...
How do I check if an index exists on a table field in MySQL?
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Use SHOW INDEX like so:
SHOW INDEX FROM [tablename]
Docs: https://dev.mysql.com/doc/refman/5.0/en/show-index.html
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Windows: XAMPP vs WampServer vs EasyPHP vs alternative [closed]
...o, but I want to open it up further to include all possible Windows/Apache/MySQL/PHP stacks.
5 Answers
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Is it possible to roll back CREATE TABLE and ALTER TABLE statements in major SQL databases?
...tive.
Is DDL transactional according to this document?
PostgreSQL - yes
MySQL - no; DDL causes an implicit commit
Oracle Database 11g Release 2 and above - by default, no, but an alternative called edition-based redefinition exists
Older versions of Oracle - no; DDL causes an implicit commit
SQL ...