How to find the differences between the values of a specific column based on a key?
- by Holicreature
I've two tables as purchase_details and invoice_details
and i want to store the inventory/stock of each product from the data of these two tables.
structure of purchase_details.
'pid', 'int(10)'
'product_id', 'int(10)'
'quantity', 'float(8,2)'
'amount', 'float(12,2)'
'expiry_date', 'date'
structure of purchase_details.
'invoice_id', 'int(10) unsigned'
'product_id', 'int(10) unsigned'
'quantity', 'float(10,2)'
'price', 'float(12,2)'
i want to calculate the total quantity of remaining stock (quantity of sum of products from purchase_details - quantity of sum of products from invoice_details).
Product_id is would be same for the two tables.
how can i proceed?