SQL: Count distinct values from one table and group by another one

Question

This is my first time here. After doing long hours of researching, I can not come across a solution to my (relatively simple) problem.

I have 2 tables:

The table "Product" has the following data:

cod_product /  cod_franchise
    2       /        1
    2       /        1
    3       /        3

The table "Item" has the following rows:

  id_item   /    cod_product
    1       /        1
    2       /        2
    3       /        2

I need to identify how many times each franchise appears (through its respective cod_product) in the "Item" table.

Therefore Im running the following SQL code:

SELECT P.COD_FRANCHISE, COUNT (I.COD_PRODUCT) AS 'QUANTITY'
FROM PRODUCT P
INNER JOIN ITEM I ON P.COD_PRODUCT = I.COD_PRODUCT
GROUP BY P.COD_FRANCHISE

But all I get with MS Access is a "TYPE MISMATCH IN EXPRESSION" ERROR Message.

Can someone please help me?

Best,

Answer 1

I've tried your query (copy/paste the code) and it works perfectly as it is.

My guess is that one of your tables' field is set to a different data type than the others . Open each table on creation mode and change all your data types to numeric or text, whichever ,as long as they're all the same.

If you don't know how/don't want to change the data types you can use this query:

SELECT P.COD_FRANCHISE*1, COUNT(I.COD_PRODUCT) AS ['QUANTITY'] FROM PRODUCT AS P INNER JOIN ITEM AS I ON P.COD_PRODUCT*1=I.COD_PRODUCT*1 GROUP BY P.COD_FRANCHISE;

The "*1" put everywhere will force Access to change your data type.