I recently published a blog post over on Medium
about the differences in 2 versions of the MySQL
COUNT() aggregate function: COUNT(*)
and COUNT(column_name or expression). I wanted to
share the post here with any readers who may be interested so
continue reading for more on this post…
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[Read more](based on a conversation with a colleague, and a bit of Twitter
)
A developer colleague paged me with this:
mysql> select
UNIX_TIMESTAMP("2021-03-26 03:07:00" + INTERVAL 2 YEAR) -
UNIX_TIMESTAMP("2021-03-26 02:07:00" + INTERVAL 2 YEAR) as delta\G
delta: 420
It is obviously wrong, and weirdly so. It only works for “2 year”, not with other values:
mysql> select
UNIX_TIMESTAMP("2021-03-26 03:07:00" + INTERVAL 1-11 year_month) -
UNIX_TIMESTAMP("2021-03-26 02:07:00" + INTERVAL 1-11 year_month) as delta\G
delta: 3600
mysql> select
UNIX_TIMESTAMP("2021-03-26 03:07:00" + INTERVAL 1-12 year_month) -
UNIX_TIMESTAMP("2021-03-26 02:07:00" + INTERVAL 1-12 year_month) as delta\G
delta: 3600
mysql> select …(based on a conversation with a colleague, and a bit of Twitter)
A Conundrum
A developer colleague paged me with this:
mysql> select
UNIX_TIMESTAMP("2021-03-26 03:07:00" + INTERVAL 2 YEAR) -
UNIX_TIMESTAMP("2021-03-26 02:07:00" + INTERVAL 2 YEAR) as delta\G
delta: 420
It is obviously wrong, and weirdly so. It only works for “2 year”, not with other values:
mysql> select
UNIX_TIMESTAMP("2021-03-26 03:07:00" + INTERVAL 1-11 year_month) -
UNIX_TIMESTAMP("2021-03-26 02:07:00" + INTERVAL 1-11 year_month) as delta\G
delta: 3600
mysql> select
UNIX_TIMESTAMP("2021-03-26 03:07:00" + INTERVAL 1-12 year_month) -
UNIX_TIMESTAMP("2021-03-26 02:07:00" + INTERVAL 1-12 year_month) as delta\G
delta: 3600
mysql> select
UNIX_TIMESTAMP("2021-03-26 03:07:00" + INTERVAL 1-13 year_month) -
UNIX_TIMESTAMP("2021-03-26 …MySQL installation security is something that should be on the mind of every MySQL DBA. While we have discussed how you should take care of your MySQL security as a whole (take a look at some of our previous posts, specifically the MySQL security series Part One and Part Two), we haven’t discussed specific security-related issues, including those issues related to privileges. We do that here.
What are Privileges in MySQL?
Privileges in MySQL can be granted to accounts. If you grant account privileges in MySQL, you determine which operations the account can perform. Privileges can be granted to either databases or database objects (tables, indexes, views etc.) Privileges can also be dynamic or static. Static privileges …
[Read more]Over the decades we have been reading the MySQL error log from the server system file, if there are any issues in MySQL or any unknown restart happened , generally we look at the mysql error log.
By default MySQL error log can be found in the default path
/var/log/mysqld.log , or it can be explicitly configured
using the variable log_error.
Few drawbacks using MySQL error log as FILE
To overcome the above issues , from MySQL …
[Read more]For MySQL, MyISAM and InnoDB storage engines are very popular. Currently, we are mostly using InnoDB engines for high reliability and high performance. Apart from those engines, we also have some other alternative engines and they have some nice features in them. In this blog, I am going to explain some of those engines, which I have listed below.
FEDERATED Storage Engine Overview:
Have you ever wondered what it takes to complete Percona Server for MySQL (PS), Percona XtraDB Cluster (PXC), and Percona XtraBackup (PXB) releases?
Let’s step back just a minute and talk about what Percona stands for. We believe we “stand on the shoulders of giants.” This means we respect our upstream sources and work to add value to the base products. Over time, new functionality is added. Much of this value-add was implemented on the 5.7 series and pulled forward to the 8.0 series. Each time we receive an upstream release, we must reapply these features to the release we receive. This process is what we call the Merge Process. …
[Read more]HelloThis is a short guide on node js mysql connection example you will learn how to connect mysql database in node js we will help you to give example of how to use mysql in node js step by step explain mysql connection in node jsIn this example i will give you simple example of how to con
In the last post I covered some of the many reasons to migrate data from a spreadsheet to a database and now it is time to show how to do just that. Moving data from a spreadsheet into MySQL can actually be pretty simple in many cases. Now I will not mislead you by telling you that all cases are easy but there is an easy way to make this migration. And I highly recommend the following process when possible as it can save lots of time. More painful migrations will be covered in the future but this post is my favorite 'fast and easy' process.
This is a guide to taking data from a spreadsheet and easily moving that data into a MySQL database instance. The trick is the Import Wizard in MySQL Workbench that does a lot of the detail work for you. In a future post we will go into what you have to do when you are not …
[Read more]Transportable tablespaces were introduced in MySQL 5.6. Using this feature, we can directly copy a tablespace to another server and populate the table with data. This is a very useful feature for large tables. The transportable tablespace mechanism is faster than any other method for exporting and importing tables because the files containing the data just need to be copied to the target location using traditional Linux commands (cp, scp, rsync). Our post MySQL 5.6 Transportable Tablespaces best practices covers the best practices about transportable tablespaces. The feature also supports encrypted tablespaces, and in this article, I am going to explain how to use this feature with them.
Requirements
Below I am sharing my current setup and the requirements.