如何将所有 InnoDB 表转换为 MyISAM？

Question

Hi guys I'm searching for a methode (sql code) with which I can convert in my WordpressDB all InnoDBs to MyISAM .

My code since now is:

SELECT CONCAT('ALTER TABLE ', TABLE_SCHEMA, '.', TABLE_NAME,' ENGINE=MyISAM;') FROM Information_schema.TABLES WHERE ENGINE = 'InnoDB'

This gives me back:

ALTER TABLE db.wp_comments ENGINE=MyISAM;
ALTER TABLE db.wp_links ENGINE=MyISAM;
ALTER TABLE db.wp_options ENGINE=MyISAM;
ALTER TABLE db.wp_postmeta ENGINE=MyISAM;
ALTER TABLE db.wp_posts ENGINE=MyISAM;
ALTER TABLE db.wp_term_relationships ENGINE=MyISAM;
ALTER TABLE db.wp_term_taxonomy ENGINE=MyISAM;
ALTER TABLE db.wp_termmeta ENGINE=MyISAM;
ALTER TABLE db.wp_terms ENGINE=MyISAM;
ALTER TABLE db.wp_usermeta ENGINE=MyISAM;
ALTER TABLE db.wp_users ENGINE=MyISAM;

Now I want to execute all of this rows at once I want to save all the results in one variable and execute them. But a sql variable can just save one row... How do I execute now all of this rows at once with just plain sql code?

Thanks in advance

PS: can I use "Update" to solve this problem as update may can update the engine to MyISAM?

Answer 1

Just tested another (simple ?) way, and worked for me.

Just export your DB as .sql file, edit-it with gedit or notepad;

Replace 'ENGINE=INNODB' with 'ENGINE=MyISAM' and Save the file edited

Number or replacement done should be the number of your tables

Import it to MySQL (phpMyAdmin or command line)

And Voila !

Answer 2

Take backup of Mysql database. Run this sql query via terminal for the database which you wish to convert into MYISAM.

mysql -h databasehostname -u username -p -e "SELECT concat('ALTER TABLE ', TABLE_NAME,' ENGINE=MYISAM;') FROM Information_schema.TABLES WHERE TABLE_SCHEMA = 'db_name' AND ENGINE = 'InnoDB' AND TABLE_TYPE = 'BASE TABLE'" | tail -n+2 >> alter.sql

Note: Change 'db_name' with your actual database name

Note: You only need the -h flag if your database is not local to the machine you are logged in to the terminal of

Import that alter.sql file into INNODB database

mysql -h databasehostname -u username -p databasename < alter.sql

Answer 3

Why? MyISAM is going away in the next release of MySQL. MyISAM is less efficient, less robust, etc, etc.

Here's how to do the ALTERs :

1. Generate alter statements into a file or the screen. (You have done that.)

2. Copy them (or feed them) into the mysql commandline tool.

3. Go get a coffee.

But watch out for errors.