Delete all products and categories from Magento 1.9.2

delete_products_and_categories_from_magento.sql

-- Foreign key check will cascade-delete all related data 

-- Delete all products
DELETE FROM catalog_product_entity;

-- Reset the autoincrement for products
ALTER TABLE catalog_product_entity AUTO_INCREMENT = 1;

-- Delete all categories
DELETE FROM catalog_category_entity WHERE `entity_id` > 2;

-- Set the proper children_count for the two categories left
UPDATE catalog_category_entity SET children_count = 1 WHERE entity_id = 1;
UPDATE catalog_category_entity SET children_count = 0 WHERE entity_id = 2;

-- Reset the autoincrement for categories
ALTER TABLE catalog_category_entity AUTO_INCREMENT = 3;