Question

Here’s my data sample:

product
--------------------------------
| product_id PK | product_name |
--------------------------------
| FRT1          | Apple        |
| FRT2          | Orange       |
| TXT1          | Ribbon       |
--------------------------------

package
-------------------------
| package_id PK | price |
-------------------------
| P001          | 1000  |
| P002          | 1500  |
| P003          | 1000  |
-------------------------

package_detail
---------------------------------
| package_id FK | product_id FK |
---------------------------------
| P001          | FRT1          |
| P002          | FRT1          |
| P002          | FRT2          |
| P003          | FRT2          |
---------------------------------

The key for searching is product_name, so if I search “Apple”, result should be like this:

-------------------------------------------
| package_id | price | num_of_package_dtl |
-------------------------------------------
| P001       | 1000  | 1                  |
| P002       | 1500  | 2                  |
-------------------------------------------

I’m weak at joining, can anyone help me with the query?
Thank you in advance~

Answer 1

SELECT  b.package_id, c.price, d.totalCount
FROM    product a
        INNER JOIN package_detail b 
            ON a.product_ID = b.product_ID
        INNER JOIN package c
            ON b.package_ID = c.package_ID
        INNER JOIN 
        (
          SELECT package_id, COUNT(*) totalCount
          FROM package_detail
          GROUP BY  package_id
        ) d ON d.package_ID = b.package_ID
WHERE a.product_name = 'apple'

SQLFiddle Demo