在连接表中找到的MySQL一对多按订单排序

Question

Two tables:

table_a
-------
table_a_id: (primary, int)

table_b
-------
table_a_id: (index, int, from table_a)
table_b_value: (varchar)

A one to many relationship between table_a_id and table_b_value.

Given a query like this:

SELECT DISTINCT(table_a_id) FROM table_a 
JOIN table_b ON table_a.table_a_id=table_b.table_a_id

I want to order by the number of occurrences of table_a_id in table_b. I'm not really sure how to write this in MySQL.

Answer 1

SELECT COUNT(table_b.table_a_id) AS count 
FROM table_a 
JOIN table_b ON table_b.table_a_id = table_a.id 
GROUP BY table_b.table_a_id 
ORDER_BY count DESC