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INTERSECT and EXCEPT commands in MySQL

MySQL now supports the INTERSECT and EXCEPT set operators. Set operators work on the results of multiple SELECT statements. In this post, we will see example queries using INTERSECT and EXCEPT commands for a better understanding

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While MySQL has supported UNION and UNION ALL commands, there were no INTERSECT or EXCEPT commands in the language. This often involved work-around queries. However, MySQL now does support the INTERCEPT and EXCEPT set operators.

For the example queries, I am using 2 simple tables with arbitrary data.

The names …

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How to Generate Test Data for MySQL With Python

For testing purposes, especially if you’re working on a project that uses any database technology to store information, you may need data to try out your project. In that case, you have two options:

  • Find a good dataset (Kaggle) or,
  • Use a library like Faker

Through this blog post, you will learn how to generate test data for MySQL using Faker.

Requirements Dependencies

Make sure all the dependencies are installed before creating the Python script that will generate the data for your project.

You can create a requirements.txt file with the following content:

pandas
sqlalchemy
PyMySQL
tqdm
faker

Once you have created this file, run the following command:

pip install -r requirements.txt

Or if you’re using Anaconda, create an environment.yml file:

name: percona
dependencies:
  - python=3.10
  - pandas
  - sqlalchemy …
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MySQL Integers: INT BIGINT and more

MySQL has a number of integer types, and while INT may seem like the right choice for most scenarios, it’s worth understanding what options you have so you can make the right choice when designing your database. In this article, we’ll take a look at the various integer types and take a deeper dive into how they are stored in MySQL. An overview of the MySQL INT type An integer is simply a whole number. It can be positive, negative, or even zero. In MySQL, there are actually several different data types you can use to store integers, each with its own range of numbers. The standards INT type can store up to 4,294,967,296 values including 0, and MySQL permits negative numbers by default unless otherwise specified. Defining an INT column looks like this in a CREATE TABLE statement:CREATE TABLE my_table ( my_integer_col INT );

Since MySQL defaults to allowing both negative and positive numbers, my_integer_col would be able to store whole …

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MySQL Integers: INT BIGINT and more

Gain a deeper understanding of the MySQL integer types by exploring the different options (INT BIGINT MEDIUMINT etc) and how they are stored.

Coroot – The Next Level in Kubernetes Observability

To follow up on my previous Kubernetes articles:

I would like to introduce a project which brings Kubernetes observability to the next …

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AlmaLinux LAMP


After installing and configuring MySQL 8.0.30, I installed the Apache Web Server, PHP and the MySQLi packages. Here are the step-by-step instructions after installing and configuring the MySQL Server and provisioning a student user and the sakila and studentdb databases (blog for those steps). After installing the major components, I completed the HTTPS configuration steps for Apache 2.

The installation steps are:

  1. Install the Apache packages as the sudoer user with this command:
    sudo dnf install -y httpd
    
  2. Enable Apache as the sudoer user with this command:
    chkconfig httpd on
    

    This returns the following completion message:

    Note: Forwarding request to 'systemctl enable httpd.service'.
    Created symlink …
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AlmaLinux MySQL+Python

After installing and configuring MySQL 8.0.30, I installed the Python connector. During that process on AlmaLinux, there were several changes since I last installed the Python’s mysql module. Here are the step-by-step instructions after installing and configuring MySQL Server (blog for those steps).

Using the MySQL Connector/Python X DevAPI Reference, you must install the pip utility before you install the library. You install the pip library as a sudoer user with the following command:

sudo yum install -y pip

Then, using the pip utility as a sudoer user install the mysql-connector-python module with the following command:

sudo pip install mysql-connector-python

Please note that this …

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Database migration with Spring Boot and Flyway

Database migration or schema evolution is inevitable in any long-lasting project. While NoSQL databases give more leeway, relational databases are pretty rigid regarding schema evolution. Hence, having a suitable tool [...]

The post Database migration with Spring Boot and Flyway appeared first on Geeky Hacker.

Galera Cluster for MySQL 5.7.39 released

Codership is pleased to announce a new Generally Available (GA) release of the multi-master Galera Cluster for MySQL 5.7, consisting of MySQL-wsrep 5.7.38 (release notes, download). This release incorporates all changes to MySQL 5.7.39, adding a synchronous option for your MySQL High Availability solutions.

We have backported the InnoDB wsrep applier lock wait timeout from 8.0 which introduces the variable innodb-wsrep-applier-lock-wait-timeout to improve the reliability in resolving …

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pt-archiver Misbehaving With Secondary Index

Not long ago, we found a long-running query in one of our clients on Managed Services. While reviewing this long-running query, we found it was generated by a pt-archiver operation. That doesn’t sound good, right?

I was able to reproduce the issue on my test environment. In this article, I will show you how to use pt-archiver to purge data from a table using a secondary index. First, we need to have the full picture before going any deeper. Here is a representation of the table structure:

Create Table: CREATE TABLE `sbtest1` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `k` int(11) NOT NULL DEFAULT '0',
  `c` char(120) NOT NULL DEFAULT '',
  `pad` char(60) NOT NULL DEFAULT '',
  PRIMARY KEY (`id`),
  KEY `k_1` (`k`)
) ENGINE=InnoDB AUTO_INCREMENT=4000001 DEFAULT …
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