Question

我想这样做：

select sum("quantity") as "sum"
from "orderArticles" 
inner join "orders" 
on "orderArticles"."orderId"="orders"."id" 
and "orderArticles"."discountTagId" = 2
and "orders"."paid" is not null;

导致我的数据库：

 sum 
-----
 151

(1 row)

我该怎么做？

我的Sequelize解决方案：

模型定义：

const order = Conn.define('orders', {
        id: {
            type: Sequelize.BIGINT,
            autoIncrement: true,
            primaryKey: true
        },
        // ...
        paid: {
            type: Sequelize.DATE,
            defaultValue: null
        },
        // ...
    },
// ...
})

const orderArticle = Conn.define('orderArticles', 
    {
        id: {
            type: Sequelize.BIGINT,
            autoIncrement: true,
            primaryKey: true
        },

        // ...

        quantity: {
            type: Sequelize.INTEGER,
            defaultValue: 1
        }
    },
    {
        scopes: {
            paidOrders: {
                include: [
                   { model: order, where: { paid: {$ne: null}} }
               ]
            }
        },
// ...
})

社团：

orderArticle.belongsTo(order)
order.hasMany(orderArticle, {onDelete: 'cascade', hooks: true})

我在经过数小时的研究后想出了这个：

db.models.orderArticles
 .scope('paidOrders') // select only orders with paid: {$ne: null}
 .sum('quantity', { // sum up all resulting quantities
    attributes: ['quantity'], // select only the orderArticles.quantity col
    where: {discountTagId: 2}, // where orderArticles.discountTagId = 2
    group: ['"order"."id"', '"orderArticles"."quantity"'] // don't know why, but Sequelize told me to
 })
.then(sum => sum) // return the sum

导致这个sql：

SELECT＆＃34; orderArticles＆＃34;。＆＃34; quantity＆＃34;，sum（＆＃34; quantity＆＃34;）AS＆＃34; sum＆＃34;，＆＃34;为了＆＃34;＆＃34; ID＆＃34; AS＆＃34; order.id＆＃34;，＆＃34; order＆＃34;。＆＃34; taxRate＆＃34; AS＆＃34; order.taxRate＆＃34;，＆＃34;为了＆＃34;＆＃34; shippingCosts＆＃34; AS＆＃34; order.shippingCosts＆＃34;，＆＃34; order＆＃34;。＆＃34; discount＆＃34; AS＆＃34; order.discount＆＃34;，＆＃34; order＆＃34;。＆＃34;付费＆＃34; AS＆＃34; order.paid＆＃34;，＆＃34;为了＆＃34;＆＃34;分派＆＃34; AS＆＃34; order.dispatched＆＃34;，＆＃34; order＆＃34;。＆＃34; payday＆＃34;如＆＃34; order.payday＆＃34;，＆＃34; order＆＃34;。＆＃34; billNr＆＃34; AS＆＃34; order.billNr＆＃34;，＆＃34;为了＆＃34;＆＃34; createdAt＆＃34; AS＆＃34; order.createdAt＆＃34;，＆＃34; order＆＃34;。＆＃34; updatedAt＆＃34;如＆＃34; order.updatedAt＆＃34;，＆＃34; order＆＃34;。＆＃34; orderCustomerId＆＃34;如＆＃34; order.orderCustomerId＆＃34;，＆＃34; order＆＃34;。＆＃34; billCustomerId＆＃34;如＆＃34; order.billCustomerId＆＃34; FROM＆＃34; orderArticles＆＃34; AS＆＃34; orderArticles＆＃34;内加入＆＃34;订单＆＃34; AS＆＃34;订单＆＃34; ON＆＃34; orderArticles＆＃34;。＆＃34; orderId＆＃34; =＆＃34; order＆＃34;。＆＃34; id＆＃34; AND＆＃34; order＆＃34;。＆＃34;付费＆＃34; IS NOT not NULL＆＃34; orderArticles＆＃34;。＆＃34; discountTagId＆＃34; = ＆＃39; 4＆＃39; GROUP BY＆＃34; order＆＃34;。＆＃34; id＆＃34;，＆＃34; orderArticles＆＃34;。＆＃34; quantity＆＃34;;

在同一数据库中有此结果：0 rows

如果你知道我的错误，请告诉我！谢谢:)）

Answer 1

找到解决方案：

在orderArticle模型的范围定义中：

scopes: {
    paidOrders: {
        include: [{ 
            model: order, 
            where: { paid: {$ne: null}}, 
            attributes: [] // don't select additional colums!
        }]
    }
},
//...

和算法：

db.models.orderArticles
    .scope('paidOrders')
    .sum('quantity', {
        attributes: [], // don't select any further cols
        where: {discountTagId: 2}
    })

注意：在我的情况下，返回承诺就足够了。我使用GraphQL解析结果并将其发送给客户端。

Sequelize：在模型A的子集上，求和关联模型B

1 个答案: