MySQL左连接条件相同的列

Question

I have tables like this:

tbl_product
===========
product_id (PK)

tbl_product_attribute
=====================
pro_attr_id (PK)
pro_attr_pro_id (FK to tbl_product)
pro_attr_attr_opt_id(FK to tbl_attribute_option)

Now, I would like query Products which have 2 attributes in the tbl_product_attribute .

Example like :

SELECT "p".* 
FROM "tbl_omx_product" "p" 
LEFT JOIN "tbl_omx_product_attribute" "proAttr" ON "proAttr".pro_attr_pro_id = p.product_id 
WHERE 
    (pro_attr_attr_opt_id LIKE '%1759%' ) AND 
    (pro_attr_attr_opt_id LIKE '%1776%' )
GROUP BY "p"."product_id";

So I'd like to get Products that has exactly 2 values at tbl_omx_product_attribute , which is 1759 & 1776.

But query like above won't show any result unless I use relation OR instead of AND .

The question what is the query to retrieve Products that have 2 values at the tbl_product_attribute ? thank you

Answer 1

To get products which have two attributes:

SELECT p.* 
FROM tbl_omx_product p 
LEFT JOIN tbl_omx_product_attribute proAttr ON proAttr.pro_attr_pro_id = p.product_id 
GROUP BY p.product_id
having count(*)=2;

You can filter data as per your required output by just adding where clause.

Answer 2

Maybe I misunderstood you, but if you want the product to have both attribute options you can query:

SELECT "p".* 
    FROM "tbl_omx_product" "p" 
    JOIN "tbl_omx_product_attribute" "proAttr1" 
        ON "proAttr1".pro_attr_pro_id = p.product_id 
            AND "proAttr1".pro_attr_attr_opt_id LIKE '%1759%'
    JOIN "tbl_omx_product_attribute" "proAttr2" 
        ON "proAttr2".pro_attr_pro_id = p.product_id 
             AND "proAttr2".pro_attr_attr_opt_id LIKE '%1776%'

Answer 3

You can try this:

SELECT p.* 
FROM tbl_omx_product AS p 
LEFT JOIN  tbl_omx_product_attribute AS proAttr ON  p.product_id = proAttr.pro_attr_pro_id
WHERE 
    (pro_attr_attr_opt_id LIKE '%1759%' ) AND 
    (pro_attr_attr_opt_id LIKE '%1776%' )
GROUP BY p.product_id;