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MYSQL: How to get rows inserted in the last X hours without querying the entire table


MYSQL: How to get rows inserted in the last X hours without querying the entire table

By : Rob
Date : November 19 2020, 03:01 PM
hope this fix your issue Let's say I have a table with 1 million rows and in the last 2 hours only 5 rows were added (each day different number of rows are being added per hour). , Consider the following table with more than a million rows:
code :
CREATE TABLE `event` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`data` varchar(11) DEFAULT NULL,
`occured_on` datetime DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (`id`),
) ENGINE=InnoDB AUTO_INCREMENT=1058669 DEFAULT CHARSET=utf8;
SELECT * FROM `event` WHERE `occured_on` > NOW() - INTERVAL 2 HOUR;
EXPLAIN SELECT * FROM `event` WHERE occured_on > NOW() - INTERVAL 2 HOUR;
id  select_type TABLE   TYPE    possible_keys   KEY     key_len ref     ROWS    Extra
1   SIMPLE      event   ALL     NULL            NULL    NULL    NULL    1053588 USING where
ALTER TABLE `event` ADD INDEX (`occured_on`);
EXPLAIN SELECT * FROM `event` WHERE occured_on > NOW() - INTERVAL 2 HOUR;
id  select_type TABLE   TYPE    possible_keys   KEY         key_len ref     ROWS    Extra
1   SIMPLE      event   RANGE   occured_on      occured_on  6       NULL    5       USING INDEX condition


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Efficiently querying a 15,000,000 rows table in MySQL

Efficiently querying a 15,000,000 rows table in MySQL


By : RedStar
Date : March 29 2020, 07:55 AM
it helps some times We NEED that explain. MyISAM offers poor concurrency. Consider that concurrent inserts may be causing you headaches. With such a large databse, InnoDB may be the direction to go. If messages are being inserted and deleted, this could be causing things to skew if your tables aren't occasionally optimized. Also, MyISAM primary keys aren't clusterd. Again, with such a large databse, InnoDB may be the direction to go.
Best practices for querying an entire row in a database table? (MySQL / CodeIgniter)

Best practices for querying an entire row in a database table? (MySQL / CodeIgniter)


By : user2070728
Date : March 29 2020, 07:55 AM
This might help you I'm not sure what you mean by "set a div's position", but here is an attemp:
controller
code :
$data = array(
    'cities' => $this->cities_model->get_cities_info()
);
$this->load->view('view',$data);
function get_cities_info()
{
  return $this->db->query('SELECT id, name, xpos, ypos FROM cities')->result();
}
<?php foreach($cities as $city) : ?>
<div style="position:absolute;top:<?= $city->ypos ?>;left:<?= $city->xpos ?>">
<?=  $city->name ?>
</div>
<?php endforearch ?>
laravel insert rows into a mysql table causes duplicate rows to be inserted

laravel insert rows into a mysql table causes duplicate rows to be inserted


By : suhail
Date : March 29 2020, 07:55 AM
Hope this helps So when I type in example.com/insert2 the function gets run even if I don't press enter and the web browser doesn't load the link. Then when I press enter and the web browser loads the link the function gets called again. Since each time the function gets called a new row is added to my mysql table, I was getting multiple rows added.
copy mysql table into another table (within the same database) and auto increment inserted rows

copy mysql table into another table (within the same database) and auto increment inserted rows


By : In Dra_ 0509
Date : March 29 2020, 07:55 AM
hope this fix your issue You need to skip the id column when inserting, so you have to list all the columns explicitly, not use SELECT *
code :
INSERT INTO wp_topic (user_id, name, subject, company, date)
SELECT user_id, name, subject, company, date
FROM wp_default_topics
Restrict users from changing rows inserted 3 hours ago in mysql

Restrict users from changing rows inserted 3 hours ago in mysql


By : Rooslunn
Date : March 29 2020, 07:55 AM
should help you out If you want to do it by using mysql, you will have to use the INTERVAL statement which will allow you to "add" time to date functions... for instance:
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