SQL: deleting tables with prefix

Question

How to delete my tables who all have the prefix myprefix_?

Note: need to execute it in phpMyAdmin

Answer 1

You cannot do it with just a single MySQL command, however you can use MySQL to construct the statement for you:

In the MySQL shell or through PHPMyAdmin, use the following query

SELECT CONCAT( 'DROP TABLE ', GROUP_CONCAT(table_name) , ';' ) 
    AS statement FROM information_schema.tables 
    WHERE table_name LIKE 'myprefix_%';

This will generate a DROP statement which you can than copy and execute to drop the tables.

EDIT: A disclaimer here - the statement generated above will drop all tables in all databases with that prefix. If you want to limit it to a specific database, modify the query to look like this and replace database_name with your own database_name:

SELECT CONCAT( 'DROP TABLE ', GROUP_CONCAT(table_name) , ';' ) 
    AS statement FROM information_schema.tables 
    WHERE table_schema = 'database_name' AND table_name LIKE 'myprefix_%';

Answer 2

Some of the earlier answers were very good. I have pulled together their ideas with some notions from other answers on the web.

I needed to delete all tables starting with 'temp_' After a few iterations I came up with this block of code:

-- Set up variable to delete ALL tables starting with 'temp_'
SET GROUP_CONCAT_MAX_LEN=10000;
SET @tbls = (SELECT GROUP_CONCAT(TABLE_NAME)
               FROM information_schema.TABLES
              WHERE TABLE_SCHEMA = 'my_database'
                AND TABLE_NAME LIKE 'temp_%');
SET @delStmt = CONCAT('DROP TABLE ',  @tbls);
-- SELECT @delStmt;
PREPARE stmt FROM @delStmt;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

I hope this is useful to other MySQL/PHP programmers.

Answer 3

show tables like 'prefix_%';

copy the results and paste them into a text editor or output the query to a file, use a few search and replaces to remove unwanted formatting and replace \n with a comma put a ; on the end and add drop table to the front.

you'll get something that looks like this:

drop table myprefix_1, myprefix_2, myprefix_3;

Answer 4

@andre-miller solution is good but there is even better and slightly more professional that will help you execute all in one go. Still will need more than one command but this solution will allow you to use the SQL for automated builds.

SET @tbls = (SELECT GROUP_CONCAT(TABLE_NAME) 
    FROM information_schema.TABLES
    WHERE TABLE_NAME LIKE 'myprefix_%');
PREPARE stmt FROM 'DROP TABLE @tbls';
EXECUTE stmt USING @tbls;
DEALLOCATE PREPARE stmt;

Note: this code is platform dependant, it's for MySQL but for sure it could be implemented for Postgre, Oracle and MS SQL with slight changes.

Answer 5

I drop table successfully by edit query to like this

SET GROUP_CONCAT_MAX_LEN=10000;
SET FOREIGN_KEY_CHECKS = 0;
SET @tbls = (SELECT GROUP_CONCAT(CONCAT('`', TABLE_NAME, '`'))
           FROM information_schema.TABLES
          WHERE TABLE_SCHEMA = 'pandora'
            AND TABLE_NAME LIKE 'temp_%');
SET @delStmt = CONCAT('DROP TABLE ',  @tbls);
-- SELECT @delStmt;
PREPARE stmt FROM @delStmt;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
SET FOREIGN_KEY_CHECKS = 1;

Answer 6

SELECT CONCAT("DROP TABLE ", table_name, ";") 
FROM information_schema.tables
WHERE table_schema = "DATABASE_NAME" 
AND table_name LIKE "PREFIX_TABLE_NAME%";

Answer 7

You can do that in one command with MySQL:

drop table myprefix_1, myprefix_2, myprefix_3;

You'll probably have to build the table list dynamically in code though.

An alternative approach would be to use the general purpose routine library for MySQL 5.

Answer 8

I just wanted to post the exact SQL I used - it's something of a mixture of the top 3 answers:

SET GROUP_CONCAT_MAX_LEN=10000;

SET @del = (
    SELECT      CONCAT('DROP TABLE ', GROUP_CONCAT(TABLE_NAME), ';')
    FROM        information_schema.TABLES

    WHERE       TABLE_SCHEMA = 'database_name'
    AND         TABLE_NAME LIKE 'prefix_%'
);

PREPARE stmt FROM @del;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

Answer 9

I found that the prepared statements were a little tricky to get working for me but setting the GROUP_CONCAT_MAX_LEN was essential when you have a lot of tables. This resulted in a simple three-step process with cut-and paste from the mysql command line that worked great for me:

SET GROUP_CONCAT_MAX_LEN=10000;
SELECT CONCAT( 'DROP TABLE ', GROUP_CONCAT(table_name) , ';' ) 
    AS statement FROM information_schema.tables 
    WHERE table_name LIKE 'myprefix_%';

Then carefully cut-and-paste the resulting long DROP statement.

Answer 10

Just another solution using GROUP_CONCAT so it will execute one drop query like
DROP TABLE table1,table2,..

SET @Drop_Stm = CONCAT('DROP TABLE ', (
      SELECT GROUP_CONCAT(TABLE_NAME) AS All_Tables FROM information_schema.tables 
      WHERE TABLE_NAME LIKE 'prefix_%' AND TABLE_SCHEMA = 'database_name'
)); 
PREPARE Stm FROM @Drop_Stm; 
EXECUTE Stm;
DEALLOCATE PREPARE Stm;