题解 | 评估不同供应商提供的零部件质量和成本情况

-- 逻辑拆解：质量评分>80,成本<50.三表连接，根据条件筛选就行
SELECT 
    t1.supplier_id,
    t2.supplier_name,
    t3.component_name,
    t1.quality_score,
    t1.cost
FROM supply_quality_cost t1
LEFT JOIN suppliers t2
ON t1.supplier_id = t2.supplier_id
LEFT JOIN components t3
ON t1.component_id = t3.component_id
WHERE t1.cost < 50
AND t1.quality_score > 80
ORDER BY t1.supplier_id,t1.cost ASC