Mysql
I recently discovered a cool function in MySQL that is nice for doing group by
queries where you want to return a column with a comma separated list of data to sum up totals. I learn best from examples so let’s look a 3 table example.
Products
CREATE TABLE products (
id int(11) NOT NULL AUTO_INCREMENT,
name varchar(255) NOT NULL,
PRIMARY KEY (id)
)
Inventory Items
CREATE TABLE inventory_items (
id int(11) NOT NULL AUTO_INCREMENT,
product_id int(11) NOT NULL,
sku varchar(255) NOT NULL,
PRIMARY KEY (id)
)
Orders
CREATE TABLE orders (
id SERIAL,
inventory_item_id INTEGER NOT NULL,
amount INTEGER NOT NULL,
PRIMARY KEY (id)
)