Mysql union, left join, group and count - mysql

Question

Heres my query
SELECT
fsi_courier_assignment_print_master_listing.master_listing_id,
fsi_master_listing.transmittal_id,
fsi_transmittals.product_name,
fsi_transmittals.transmittal_id
FROM fsi_courier_assignment_print_master_listing
LEFT JOIN fsi_master_listing ON fsi_courier_assignment_print_master_listing.master_listing_id = fsi_master_listing.master_listing_id
LEFT JOIN fsi_transmittals ON fsi_master_listing.transmittal_id = fsi_transmittals.transmittal_id
WHERE dispatch_code_id=".$this->db->escape($dispatch_code_id)."
UNION ALL
SELECT
fsi_courier_assignment_print_master_listing_undelivered.master_listing_id,
fsi_master_listing.transmittal_id,
fsi_transmittals.product_name,
fsi_transmittals.transmittal_id
FROM fsi_courier_assignment_print_master_listing_undelivered
LEFT JOIN fsi_master_listing ON fsi_courier_assignment_print_master_listing_undelivered.master_listing_id = fsi_master_listing.master_listing_id
LEFT JOIN fsi_transmittals ON fsi_master_listing.transmittal_id = fsi_transmittals.transmittal_id
WHERE dispatch_code_id=".$this->db->escape($dispatch_code_id)."
fsi_courier_assignment_print_master_listing table
master_listing_id dispatch_code_id
2 2
5 2
36 2
37 2
134 2
135 2
136 2
137 2
138 2
139 2
140 2
fsi_courier_assignment_print_master_listing_undelivered table
master_listing_id dispatch_code_id
1 2
fsi_master_listing table
master_listing_id transmittal_id
1 1
2 1
5 2
36 2
37 2
134 3
135 3
136 3
137 3
138 3
139 3
140 3
fsi_transmittals table
transmittal_id product_name
1 Name 1
2 Name 2
3 Name 3
What Im trying to do is to get the combined result of product from fsi_courier_assignment_print_master_listing and fsi_courier_assignment_print_master_listing_undelivered where dispatch_code_id='2' and count them
My desire Output would be
Product Name Product Count
Name 1 2
Name 2 3
Name 3 7
Thanks in advance, hope somebody can help me to this..

Answer 1

Your query is fine, you just need to:
Add COUNT with GROUP BY product_name and put your query as a subquery.
The transmittal_id is specified two times in the two union queries, either remove one of them or give them different names (It might work fine in MySQL, but it is recommended not to do so).
So your query will be something like this:
SELECT
t.product_name,
COUNT(*) AS ProductCount
FROM
(
SELECT
ml.master_listing_id,
m.transmittal_id,
t.product_name
FROM fsi_courier_assignment_print_master_listing AS ml
LEFT JOIN fsi_master_listing AS m
ON ml.master_listing_id = m.master_listing_id
LEFT JOIN fsi_transmittals AS t
ON m.transmittal_id = t.transmittal_id
UNION ALL
SELECT
u.master_listing_id,
m.transmittal_id,
t.product_name
FROM fsi_courier_assignment_print_master_listing_undelivered as u
LEFT JOIN fsi_master_listing AS m
ON u.master_listing_id = m.master_listing_id
LEFT JOIN fsi_transmittals AS t
ON m.transmittal_id = t.transmittal_id
) AS t
GROUP BY t.product_name;
This will give you: