Pst7 combine SQL similar rows

Question

Right now I have made two tables to store user data and all transactions what users made. Structure of transaction table looks like this:

id          user        symbol      price       quantity    total       name                  type
----------  ----------  ----------  ----------  ----------  ----------  --------------------------  ----------------
     1       user1     A           55.43       2           110.86      Agilent Technologies, Inc.           buy             
     1       user1     A           53.25       3           159.75      Agilent Technologies, Inc.          buy  

With query SELECT * WHERE user = 'user1' i can select all transactions user1 made, but how can I combine these two rows in one and quantities sums up? Is this even possible in SQL?

Answer 1

You would use the aggregate function SUM(). A simple example would be:

SELECT sum(quantity) from transactions where .....

• You can sum multiple columns like SELECT sum(quantity), sum(total) from ....
• The "result" column name would be accessed like row["sum(quantity)"]

This should be enough to get you started, you will likely have to experiment to get exactly what you want.