如何使用左/外联接简化此MYSQL查询？

Question

select 
    sp2.sale_id, 
    sum(sp2.payment_amount) as sumpaid, 
    sik2.quantity_purchased, 
    sik2.item_kit_unit_price,
    sik2.discount_percent,  
    min(sp2.payment_date) as payment_date 
from 
    sales_payments sp2, 
    sales_item_kits sik2, 
    sales_item_kits_taxes sit2
where 
    sik2.sale_id=sp2.sale_id
    and sit2.sale_id=sp2.sale_id
group by 
    sp2.sale_id

Please help simplifying this query with (OUTER/LEFT?) JOIN which all of table doesn't have same rows amount.. thanks in advance

Answer 1

i did not get why are you using skt2 table.

select 
    sp2.sale_id, 
    sum(sp2.payment_amount) as sumpaid, 
    sik2.quantity_purchased, 
    sik2.item_kit_unit_price,
    sik2.discount_percent,  
    min(sp2.payment_date) as payment_date 
from 
    sales_payments sp2 LEFT JOIN  
    sales_item_kits sik2 ON sik2.sale_id=sp2.sale_id LEFT JOIN 
    sales_item_kits_taxes sit2 ON sit2.sale_id=sp2.sale_id

group by 
    sp2.sale_id