mysql table not decreased in size after deleting rows

Question

I deleted 1M rows from a database table. Surprisingly its size did not decrease. Then I have tried: FLUSH TABLES; but whey I ran this statement on phpMyAdmin of my cPanel then I encountered below error:

#1227 - Access denied; you need (at least one of) the RELOAD privilege(s) for this operation

How can I decrease my table size and clear its cache?

Answer 1

Try optimize table command

OPTIMIZE TABLE <tablename>;

Answer 2

In phpMyAdmin, click on the database name to show the tables in the main panel. Then tick the checkbox next to the table name you want to decrease, and in the "With selected" drop-down under the list of tables, choose "Optimize".