上一页的最后一个元素作为 Sequelize 分页中下一页的第一个元素

Question

我正在使用 MySQL 作为 Sequelize 分页的数据库。我将上一页的最后一个元素作为下一页的第一个元素。

exports.searchProductCategories = (body, username, shopId) => {
return new Promise((resolve, reject) => {
    let searchText = body.searchText.toLowerCase();
    let limit = body.limit;
    let offset = body.offset;
    Category.findAndCountAll({
        where: {
            [Sequelize.Op.or]:[
                {name: Sequelize.where(Sequelize.fn('LOWER', Sequelize.col(KEY_NAME_COLUMN)), Sequelize.Op.like, '%' + searchText + '%')},
                {description: Sequelize.where(Sequelize.fn('LOWER', Sequelize.col(KEY_DESCRIPTION_COLUMN)), Sequelize.Op.like, '%' + searchText + '%')}
            ],
            [Sequelize.Op.and]:[
                {shopId: Sequelize.where(Sequelize.col(KEY_SHOP_ID_COLUMN), Sequelize.Op.eq, shopId)}
            ]
        },
        order: [
            [KEY_NAME_COLUMN, 'ASC']
        ],
        offset: offset,
        limit: limit
      }).then(result => {
        resolve ({ [KEY_STATUS]: 1, [KEY_MESSAGE]: "Categories listed successfully", [KEY_DATA]: result.rows, [KEY_TOTAL_COUNT]: result.count });
    }).catch(error => { 
        reject ({ [KEY_STATUS]: 0, [KEY_MESSAGE]: "Categories list failed" + error });
    });
})
}

以上代码，我给

{
"searchText": "cat",
"limit": 2,
"offset": 0
}

然后我得到了 2 件商品。接下来，我给

{
"searchText": "cat",
"limit": 2,
"offset": 1
}

然后我将上一页的最后一个元素作为当前页面的第一个元素。

Answer 1

您应该使用 page 和 limit 来计算偏移量例如：

    page = 1 // for first page
    offset = (page - 1) * limit   // for the first page it skips (1 - 1) * 2 = 0 records and show 2(limits) records

第二页

limit = 2
page = 2
offset = (2-1)*2 = 2 // so it skips 2 records and show next 2 records

上一页的最后一个元素作为 Sequelize 分页中下一页的第一个元素

Last element of previous page come as first element of next page in Sequelize pagination

pagination

sequelize.js

sequelize-typescript