Questions tagged [mysql]

MySQL is a free, open-source Relational Database Management System (RDBMS) that uses Structured Query Language (SQL). DO NOT USE this tag for other DBs such as SQL Server, SQLite etc. Those are different DBs that all use their own dialects of SQL to manage the data. Always specify the exact version of the server in the question. Versions 5.x differ greatly in their capabilities from versions 8+.

MySQL is an Open Source RDBMS (Relational Database Management System) that runs as a server providing multi-user access to several databases. Its source code is available under the GNU GPL (General Public License). MySQL was acquired by Oracle in 2009.

MariaDB is a fork of MySQL using the same dialect of SQL and offering most of the same functions. See for fork-specific questions and answers.

MySQL offers standard database driver connectivity for using MySQL with applications and tools compatible with industry standards ODBC and JDBC.

How to ask a good and answerable question

Please see this post: Tips for asking a good Structured Query Language (SQL) question to get tips on how to ask a question about MySQL. Following some of these steps will help people to help you solve your problem.

Minimal, reproducible examples help the Stack Overflow community give good answers. Please read Why should I provide a Minimal Reproducible Example for a very simple SQL query?.

Always specify the exact version of the server in the question. Versions 5.x differ greatly in their capabilities from versions 8+.


Officially it is /maɪˌɛskjuːˈɛl/ ("My S-Q-L"), but is often pronounced /maɪˈsiːkwəl/ ("My Sequel").

Latest Version (MySQL Community Server 8.0.27) and Version History




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661202 questions
40 answers

Should I use the datetime or timestamp data type in MySQL?

Would you recommend using a datetime or a timestamp field, and why (using MySQL)? I'm working with PHP on the server side.
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How can I prevent SQL injection in PHP?

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to SQL injection, like in the following example: $unsafe_variable = $_POST['user_input']; mysql_query("INSERT INTO `table` (`column`) VALUES…
Andrew G. Johnson
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55 answers

How do I import an SQL file using the command line in MySQL?

I have a .sql file with an export from phpMyAdmin. I want to import it into a different server using the command line. I have a Windows Server 2008 R2 installation. I placed the .sql file on the C drive, and I tried this command database_name <…
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Why shouldn't I use mysql_* functions in PHP?

What are the technical reasons for why one shouldn't use mysql_* functions? (e.g. mysql_query(), mysql_connect() or mysql_real_escape_string())? Why should I use something else even if they work on my site? If they don't work on my site, why do I…
Madara's Ghost
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2 answers

What's the difference between INNER JOIN, LEFT JOIN, RIGHT JOIN and FULL JOIN?

What's the difference between INNER JOIN, LEFT JOIN, RIGHT JOIN and FULL JOIN in MySQL?
Lion King
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12 answers

Installing specific package version with pip

I am trying to install version 1.2.2 of MySQL_python, using a fresh virtualenv created with the --no-site-packages option. The current version shown in PyPi is 1.2.3. Is there a way to install the older version? I have tried: pip install…
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27 answers

SQL select only rows with max value on a column

I have this table for documents (simplified version here): id rev content 1 1 ... 2 1 ... 1 2 ... 1 3 ... How do I select one row per id and only the greatest rev? With the above data, the result should contain two rows: [1, 3,…
25 answers

How to reset AUTO_INCREMENT in MySQL

How can I reset the AUTO_INCREMENT of a field? I want it to start counting from 1 again.
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16 answers

Can I concatenate multiple MySQL rows into one field?

Using MySQL, I can do something like: SELECT hobbies FROM peoples_hobbies WHERE person_id = 5; My Output: shopping fishing coding but instead I just want 1 row, 1 col: Expected Output: shopping, fishing, coding The reason is that I'm selecting…
Dean Rather
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40 answers

How can I output MySQL query results in CSV format?

Is there an easy way to run a MySQL query from the Linux command line and output the results in CSV format? Here's what I'm doing now: mysql -u uid -ppwd -D dbname << EOQ | sed -e 's/ /,/g' | tee list.csv select id, concat("\"",name,"\"") as…
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How can I get a list of user accounts using the command line in MySQL?

I'm using the MySQL command-line utility and can navigate through a database. Now I need to see a list of user accounts. How can I do this? I'm using MySQL version 5.4.1.
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13 answers

Which MySQL data type to use for storing boolean values

Since MySQL doesn't seem to have any 'boolean' data type, which data type do you 'abuse' for storing true/false information in MySQL? Especially in the context of writing and reading from/to a PHP script. Over time I have used and seen several…
13 answers

UTF-8 all the way through

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1. Where exactly do I need to set the encoding/charsets?…
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34 answers

Retrieving the last record in each group - MySQL

There is a table messages that contains data as shown below: Id Name Other_Columns ------------------------- 1 A A_data_1 2 A A_data_2 3 A A_data_3 4 B B_data_1 5 B B_data_2 6 C C_data_1 If…
Vijay Dev
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9 answers

What's the difference between utf8_general_ci and utf8_unicode_ci?

Between utf8_general_ci and utf8_unicode_ci, are there any differences in terms of performance?
KahWee Teng
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