Question

如果我想从给定以下参数的表中获取所有列，以下分页查询可以正常工作

getOrdersPagination(limit, after) {

    let where = '';
    if (after > 0) {
        where = `id < ${after}`;
    }

    return knex
        .select(
            'id',
            'patient_id AS patientId',
            'pharmacy_id AS pharmacyId',
            'customer_id AS customerId',
            'department_id AS departmentId',
            'user_id AS userId',
            'status',
            'info',
            'created_at AS createdAt'
        )
        .from('order')
        .whereRaw(where)
        .orderBy('id', 'desc')
        .limit(limit);
}

但是，如果我传递另一个参数（在本例中为status）以进一步过滤掉返回的行，我将获得与上述查询完全相同的输出。 status字段（整数）对我的getOrdersByStatusPagination查询没有任何影响。

getOrdersByStatusPagination(limit, after, status) {

    let where = '';
    if (after > 0) {
        where = `id < ${after} AND status = ${status}`;
    }

    return knex
        .select(
            'id',
            'patient_id AS patientId',
            'pharmacy_id AS pharmacyId',
            'customer_id AS customerId',
            'department_id AS departmentId',
            'user_id AS userId',
            'status',
            'info',
            'created_at AS createdAt'
        )
        .from('order')
        .whereRaw(where)
        .orderBy('id', 'desc')
        .limit(limit);
}

我想知道我是否正确使用whereRaw子句来使用AND运算符包含多个where语句。

http://knexjs.org/#Builder-whereRaw

我还可以包含查询的示例JSON输出，但我不确定这是否有任何帮助，因为它只是从提到的列中获取所有数据。

Answer 1

我发现的一个解决方案是在查询中使用另一个where子句以及whereRaw。但我还是想听听有人知道如何在status选项中使用whereRaw arg

另一个where子句的解决方案

getOrdersByStatusPagination(limit, after, status) {

    let where = '';
    if (after > 0) {
        where = `id < ${after}`;
    }

    return knex
        .select(
            'id',
            'patient_id AS patientId',
            'pharmacy_id AS pharmacyId',
            'customer_id AS customerId',
            'department_id AS departmentId',
            'user_id AS userId',
            'status',
            'info',
            'created_at AS createdAt'
        )
        .from('order')
        .whereRaw(where)
        .where('status', '=', status)
        .orderBy('id', 'desc')
        .limit(limit);
}

Answer 2

所以，这是解决问题的knex方法

基本理念是。您创建knex构建器的实例并有条件地向其添加子句。

getOrdersByStatusPagination (limit, after, status) {
    const builder = knex
        .select(
            'id',
            'patient_id AS patientId',
            'pharmacy_id AS pharmacyId',
            'customer_id AS customerId',
            'department_id AS departmentId',
            'user_id AS userId',
            'status',
            'info',
            'created_at AS createdAt'
        )
        .from('order')
        .whereRaw(where)
        .where('status', status) // No need for '=' argument. Knex inserts it by default
        .orderBy('id', 'desc')
        .limit(limit);

    if (after > 0) {
        builder.where('id', '<', after) // No need for .whereRaw method. You can use the same as for statuses' '='
        // or builder.whereRaw(`id < ${after}`)
    }
    return builder
}

在knex中使用whereRaw子句为postgres客户端

2 个答案: