How to SUM and SUBTRACT using SQL?

Question

I am using MySQL and I have two tables:

master_table

• ORDERNO
• ITEM
• QTY

stock_bal

Answer 1

Simple copy & paste example with subqueries, Note, that both queries should return 1 row:

select
(select sum(items_1) from items_table_1 where ...)
-
(select count(items_2) from items_table_1 where ...) 

as difference