假如你有这样的一个数据：

[
    {
        "bigClass":"吃的",
        "smallClass":"水果",
        "item":"苹果"
    },
    {
        "bigClass":"吃的",
        "smallClass":"水果",
        "item":"香蕉"
    },
    {
        "bigClass":"吃的",
        "smallClass":"面食",
        "item":"刀削面"
    },
    {
        "bigClass":"吃的",
        "smallClass":"面食",
        "item":"拉面"
    },
    {
        "bigClass":"喝的",
        "smallClass":"碳酸饮料",
        "item":"可乐"
    },
    {
        "bigClass":"坐的",
        "smallClass":"车",
        "item":"奥迪"
    },
    {
        "bigClass":"坐的",
        "smallClass":"车",
        "item":"奔驰"
    },
    {
        "bigClass":"用的",
        "smallClass":"工作用的",
        "item":"电脑"
    }
]

需求如下：

代码实现：

const columns: any = [
    {
        title: '业务方向',
        dataIndex: 'bigClass',
        key: 'bigClass',
        onCell: (record: any) => {
            // 新增一个lineRowSpan记录该合并的行数
            return {rowSpan: record.lineRowSpan};
        }
    },
    {
        title: '子业务',
        dataIndex: 'smallClass',
        key: 'smallClass',
        onCell: (record: any) => {
            // 新增一个subLineRowSpan记录该合并的行数
            return {rowSpan: record.subLineRowSpan};
        }
    },
    {
        title: '功能模块',
        dataIndex: 'item',
        key: 'item'
    }
];

// 处理数据的函数，主要是加上行数的属性
const handleDataSource = (data: any[]) => {
    const lineCounts: any = {};
    data.forEach((obj) => {
        const bigClass = obj.bigClass;
        const smallClass = obj.smallClass;
        lineCounts[bigClass] = (lineCounts[bigClass] || 0) + 1;
        lineCounts[smallClass] = (lineCounts[smallClass] || 0) + 1;
        const a = data.filter(o => o.bigClass === bigClass).length;
        const b = data.filter(o => o.smallClass === smallClass).length;
        obj.lineRowSpan = lineCounts[bigClass] === 1 ? a : 0;
        obj.subLineRowSpan = lineCounts[smallClass] === 1 ? b : 0;
    });
    return data;
};

// 展开函数处理
const handleExpand = (expanded: boolean, record: any) => {
    if (record.funcModule === expandedRowKey) {
        setExpandedRowKey('');
    } else {
        setExpandedRowKey(record.item);
        getExpandData(getFuncModuleCode(record.item), startDate, endDate);
    }
    //展开时，对原始数据进行修改
    expanded && setServiceData(handleExpandDataSource(record.item));
    //不展开，使用原始数据进行渲染即可
    !expanded && setServiceData(initData);
};

// 举例
const handleExpandDataSource = (item: string) => {
        let newArr: any = [];
        if (item === '苹果' || item === '香蕉') {
            newArr = initData?.map((item) => {
                if (item.item === '苹果') {
                    return {
                        ...item,
                        lineRowSpan: 5,
                        subLineRowSpan: 3
                    };
                } else {
                    return item;
                }
            });
        }
        return newArr;
    };