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Tuesday, July 23, 2013

DROP all MySQL Database tables from the command line!!


DROP all MySQL tables from the command line

I had a situation today where I wanted to drop all the tables in a database, but didn't have access to a UI like phpMyAdmin. The easiest thing to do would have been to drop the entire database then re-create it, but I didn't have permissions to drop an entire database.
After searching around online, this is the best solution I found:
mysqldump -u username -p --no-data dbname | grep ^DROP > drop.sql
mysql -u username -p dbname < drop.sql
rm drop.txt
Simple, and only requires 2 lines (ok, a 3rd line for cleanup).
What these commands do is basically generated a mysqldump file (which included DROP commands by default), then filter the output to only show the lines that have the DROP statements. The arrow (>) redirects the output to a file. The second line then imports those SQL statements into the database.
Another option I have is to use information_schema database and generate an sql script like below :

Select concat('DROP TABLE database_name.', table_name,';') from information_schema.TABLES where table_schema='database_name';
Which gives:
DROP TABLE database_name.table_name1;
...
DROP TABLE database_name.table-nameN;

You can pipe it to be executed directly. I prefer this syntax than the DROP TABLE IF EXISTS table_name1;
Note : Replace database_name with your DB Name. Also, sometime if we execute generated script, then it may throw exceptions if tables have dependencies with each other. In such case you have to first delete master table and then dependent table.