如何使用 Vue3 和 Element Plus 实现复杂的表格，支持动态行列生成和二级分类数据的渲染，并实现单元格合并功能？

<el-table :span-method="arrayspanmethod" :data="tabledata">
    <el-table-column
      label="派出组"
      align="center"
      prop="group"></el-table-column>
    <el-table-column
      label="累计生产单"
      align="center"
      prop="total"></el-table-column>
    <el-table-column
      label="案件主办"
      align="center"
      prop="person"></el-table-column>
    <el-table-column
      v-for="(item, index) in headerlist"
      :key="index"
      :label="item.label"
      align="center"
      :prop="item.prop">
      <el-table-column
        v-for="(list, i) in item.sublist"
        :key="i"
        :label="list.label"
        align="center"
        :prop="list.prop">
        <template #default="scope">{{
          scope.row[item.prop][list.prop]
        }}</template>
      </el-table-column>
    </el-table-column>
  </el-table>

// 模拟后台返回的表格头部信息
const headerList = ref([
  {
    label: '达飞',
    prop: 'column1',
    subList: [
      {
        label: '保理当日',
        prop: 'day'
      },
      {
        label: '保理累计',
        prop: 'total'
      }
    ]
  },
  {
    label: '农行',
    prop: 'column2',
    subList: [
      {
        label: '农行秦分当日',
        prop: 'day'
      },
      {
        label: '农行秦分累计',
        prop: 'total'
      }
    ]
  }
])
// 模拟后台返回的表格数据信息
const tableData1 = ref([
  {
    group: '海港组',
    total: 123,
    person: 'aa',
    column1: {
      day: '500',
      total: 3000
    },
    column2: { day: 100, total: 3000 }
  },
  {
    group: '海港组',
    total: 123,
    person: 'bb',
    column1: {
      day: '500',
      total: 3000
    },
    column2: { day: 100, total: 3000 }
  },
  {
    group: '海港组',
    total: 123,
    person: 'cc',
    column1: {
      day: '500',
      total: 3000
    },
    column2: { day: 100, total: 3000 }
  },
  {
    group: '其他组',
    total: 123,
    person: 'cc',
    column1: {
      day: '500',
      total: 3000
    },
    column2: { day: 100, total: 3000 }
  },
  {
    group: '其他组',
    total: 123,
    person: 'cc',
    column1: {
      day: '500',
      total: 3000
    },
    column2: { day: 100, total: 3000 }
  },
  {
    group: '其他组',
    total: 234,
    person: 'cc',
    column1: {
      day: '500',
      total: 3000
    },
    column2: { day: 100, total: 3000 }
  }
])
const groupArr = ref([]) // 用于合并组
const groupPos = ref(0) // 合并行数默认值
const totalArr = ref([]) // 用于合并生产单
const totalPos = ref(0) // 合并生产单默认值

// 表格行合并方法
const merge = (tableData) => {
  // 要合并的数组的方法
  groupArr.value = []
  groupPos.value = 0
  totalArr.value = []
  totalPos.value = 0

  for (var i = 0; i < tableData.length; i++) {
    if (i === 0) {
      // 第一行必须存在
      groupArr.value.push(1)
      groupPos.value = 0

      totalArr.value.push(1)
      totalPos.value = 0
    } else {
      // 判断当前元素与上一个元素是否相同 this.groupPos是groupArr内容的序号
      if (tableData[i].group === tableData[i - 1].group) {
        groupArr.value[groupPos.value] += 1
        groupArr.value.push(0)
      } else {
        groupArr.value.push(1)
        groupPos.value = i
      }

      // 生产单合并
      if (
        tableData[i].total === tableData[i - 1].total &&
        tableData[i].group === tableData[i - 1].group
      ) {
        totalArr.value[totalPos.value] += 1
        totalArr.value.push(0)
      } else {
        totalArr.value.push(1)
        totalPos.value = i
      }
    }
  }
}
// 合并行
const arraySpanMethod = ({ row, column, rowIndex, columnIndex }) => {
  if (columnIndex === 0) {
    // 合并组
    const _row_1 = groupArr.value[rowIndex]
    const _col_1 = _row_1 > 0 ? 1 : 0 // 如果被合并了_row=0则它这个列需要取消
    return {
      rowspan: _row_1,
      colspan: _col_1
    }
  } else if (columnIndex === 1) {
    // 第二列的合并方法,合并生产单
    const _row_2 = totalArr.value[rowIndex]
    const _col_2 = _row_2 > 0 ? 1 : 0
    return {
      rowspan: _row_2,
      colspan: _col_2
    }
  }
}
merge(tableData.value)