How to change a MySQL database’s table prefix

Changing a database table prefix is easy and here’s the simple step-by-step guide! For WordPress installations, it’s essential!
How to change a prefix
1. In your text editor, change database_name, old_prefix_ and new_prefix_ to the required values:
SET @database = "database_name";
SET @old_prefix = "old_prefix_";
SET @new_prefix = "new_prefix_";
SELECT
concat(
"RENAME TABLE ",
TABLE_NAME,
" TO ",
replace(TABLE_NAME, @old_prefix, @new_prefix),
';'
) AS "SQL" 

FROM information_schema.TABLES WHERE TABLE_SCHEMA = @database;

2. Run the query in cPanel or PHPMyAdmin on your WordPress database
3. The output will be a series of SQL queries that will rename the tables for you
4. Run the output
5. Done!
 
How to add a prefix 
 
If your database doesn’t have a prefix at all, follow the steps above but use the below query that’s been slightly modified for this purpose:
SET @database = "database_name";
SET @prefix = "prefix_";
SELECT
concat(
"RENAME TABLE ",
TABLE_NAME,
" TO ",
@prefix,
TABLE_NAME,
';'
) AS "SQL" 

FROM information_schema.TABLES WHERE TABLE_SCHEMA = @database;