mysql - Most efficient way to get table row count

Question

I currently have a database with over 6 million rows and growing. I currently do SELECT COUNT(id) FROM table; in order to display the number to my users, but the database is getting large and I have no need to store all of those rows except to be able to show the number. Is there a way to select the auto_increment value to display so that I can clear out most of the rows in the database? Using LAST_INSERT_ID() doesn't seem to work.

Answer 1

Following is the most performant way to find the next AUTO_INCREMENT value for a table. This is quick even on databases housing millions of tables, because it does not require querying the potentially large information_schema database.

mysql> SHOW TABLE STATUS LIKE 'table_name';
// Look for the Auto_increment column

However, if you must retrieve this value in a query, then to the information_schema database you must go.

SELECT `AUTO_INCREMENT`
FROM   INFORMATION_SCHEMA.TABLES
WHERE  TABLE_SCHEMA = 'DatabaseName'
AND    TABLE_NAME   = 'TableName';