我正在做一个查询以返回存储在sb_carts表中的所有用户购物车。存储在sb_carts中的产品信息通过两个关键字product_sku和school_id引用。它需要参考两个返回唯一的产品与独特的库存水平等MYSQL内部通过两个键加入两个表
当我执行下面的查询它返回一行,我期待3行。 我已经尝试将内部连接分解为两个单独的连接,但这仍然只返回1个结果。仅加入一个密钥就能获得理想的结果,但可能会重新调整错误的产品。左联接返回3行,但某些数据丢失特定产品
下面是我在做什么
SELECT sb_carts.product_sku FROM sb_carts INNER JOIN sb_products ON sb_products.sku = sb_carts.product_sku AND sb_products.school_id = sb_carts.school_id WHERE sb_carts.order_id = 0 AND sb_carts.user_id = 2 GROUP BY sb_carts.cart_id
完整的查询看起来简单的例子像
SELECT COUNT(DISTINCT sb_carts.cart_id) as quantity, sb_carts.* FROM sb_carts INNER JOIN sb_children ON sb_children.child_id = sb_carts.child_id INNER JOIN sb_school_entities ON sb_school_entities.school_id = sb_children.school_id INNER JOIN sb_products ON sb_products.sku = sb_carts.product_sku AND sb_products.school_id = sb_carts.school_id LEFT JOIN sb_houses ON sb_children.house_id = sb_houses.id LEFT JOIN sb_refund_cart ON sb_carts.cart_id = sb_refund_cart.cart_id WHERE sb_carts.order_id = 0 AND sb_carts.user_id = 2 GROUP BY sb_carts.child_id, sb_carts.product_sku, sb_carts.school_id ORDER BY sb_children.dob_year, sb_children.dob_month, sb_children.dob_day ASC
是的,情况正是如此。如果您使用GROUP BY,MySQL不会强制您使用聚合函数(例如,与MS-SQL不同,例如,该查询无效) –