如何在mysql中用多个条件排序

Question

I have a table like the following with 2 columns product_id, main_product_id and location. main_product_id contains the product_id of a main product.

+-------------+--+--------------+--+-----------+
| product_id  |  | main_prod_id |  | location  |
+-------------+--+--------------+--+-----------+
| product1    |  |              |  | AE 34 CH  |
| product2    |  |              |  | AE 46 CH  |
| product3    |  |              |  | V         |
| sub_prod_1  |  | product3     |  |           |
| sub_prod_2  |  | product3     |  |           |
| sub_prod_3  |  | product3     |  | AK 22 AUS |
| sub_prod_4  |  | product3     |  | CI 06 FR  |
| sub_prod_5  |  | product3     |  | TA ee ES  |
| sub_prod_6  |  | product3     |  | V         |
| product4    |  |              |  | CT 01 FR  |
| product5    |  |              |  | V         |
| sub_prod_7  |  | product5     |  |           |
| sub_prod_8  |  | product5     |  |           |
| sub_prod_9  |  | product5     |  | ED 2 ES   |
| sub_prod_10 |  | product5     |  | EN 02 ES  |
| sub_prod_11 |  | product5     |  | TB 03 ES  |
| sub_prod_12 |  | product5     |  | V         |
+-------------+--+--------------+--+-----------+

sub_prod_12 product5 V

I want to sort

• First the products that are not in main product like product1, product2 and product4 ordered by the location, (Type1 products)
• then the products that are in main product column like product3, product5,(Type2 products)
• after each main product there will be it's sub products ordered by location.(Sub products of type 2 products)

So the final result should look like this

+-------------+--+--------------+-----------+
| Product_id  |  | main_prod_id | location  |
+-------------+--+--------------+-----------+
| product1    |  |              | AE 34 CH  |
| product2    |  |              | AE 46 CH  |
| product4    |  |              | CT 01 FR  |
| product3    |  |              | V         |
| sub_prod_1  |  | product3     |           |
| sub_prod_2  |  | product3     |           |
| sub_prod_3  |  | product3     | AK 22 AUS |
| sub_prod_4  |  | product3     | CI 06 FR  |
| sub_prod_5  |  | product3     | TA ee ES  |
| sub_prod_6  |  | product3     | V         |
| product5    |  |              | V         |
| sub_prod_7  |  | product5     |           |
| sub_prod_8  |  | product5     |           |
| sub_prod_9  |  | product5     | ED 2 ES   |
| sub_prod_10 |  | product5     | EN 02 ES  |
| sub_prod_11 |  | product5     | TB 03 ES  |
| sub_prod_12 |  | product5     | V         |
+-------------+--+--------------+-----------+

It's possible that the table may have only type 1 products or both type 2 and it's sub products or all types of products.

My query so far is the following

SELECT 
    mt.product_id, mt.main_prod_id, mt.location
FROM
    my_table mt
ORDER BY (CASE
    WHEN
        mt.product_id NOT IN (SELECT 
                main_prod_id
            FROM
                my_table)
            AND (mt.main_prod_id = ''
            OR mt.main_prod_id IS NULL)
    THEN
        mt.location
    WHEN
        mt.product_id IN (SELECT 
                main_prod_id
            FROM
                my_table)
            AND (mt.main_prod_id = ''
            OR mt.main_prod_id IS NULL)
    THEN
        mt.product_id
    ELSE mt.main_prod_id
END) ASC , (CASE
    WHEN
        mt.product_id NOT IN (SELECT 
                main_prod_id
            FROM
                my_table)
            AND (mt.main_prod_id = ''
            OR mt.main_prod_id IS NULL)
    THEN
        0
    WHEN
        mt.product_id IN (SELECT 
                main_prod_id
            FROM
                my_table)
            AND (mt.main_prod_id = ''
            OR mt.main_prod_id IS NULL)
    THEN
        1
    ELSE 2
END) ASC , mt.location ASC

But with the above query what I'm getting is the first table.

Answer 1

Could you give this a try?

SELECT 
    product_id, main_prod_id, location
FROM
    my_table
ORDER BY 
    CONCAT(main_prod_id,product_id), location;

Comments:

1. This might not the final solution, I haven't tested it, but it might give you some hints.

2. You didn't sort out your sorting conditions properly before your started writing the query.

3. You cannot do, what you tried to do, in the ORDER BY expressions.