vue中如何使用elementUI表格动态行合并

<el-table
        :data="tableData"
        border
        :span-method="objectSpanMethod"
      >
        <el-table-column label="前面" align="center">
          <el-table-column prop="inquiryCode" label="id" align="center" />
          <el-table-column prop="phoneNumber" label="1" align="center" />
          <el-table-column prop="createTime" label="2" align="center" />
          <el-table-column prop="createTime" label="3" align="center" />
          <el-table-column prop="contractCount" label="4" align="center" />
        </el-table-column>
        <el-table-column label="中间" align="center">
          <el-table-column prop="bankName" label="6" align="center" />
          <el-table-column prop="acceptanceAmount" label="7" align="center" />
          <el-table-column prop="dueTime" label="8" align="center" />
          <el-table-column prop="dueDay" label="9" align="center" />
          <el-table-column prop="interestAmount" label="10" align="center" />
        </el-table-column>
        <el-table-column label="总计" align="center">
          <el-table-column prop="cashPayAmount" label="11" align="center" />
          <el-table-column prop="acceptanceAllAmount" label="12" align="center" />
          <el-table-column prop="payAllAmount" label="13" align="center" />
          <el-table-column prop="interestAllAmount" label="14" align="center" />
        </el-table-column>
      </el-table>

export default {
  data() {
    return {
      tableData: [],
      spanArr: [],
     }
  },
  mounted() {
    this.rowspan();
  },
  methods: {
    rowspan() {
      // 每次调用清空数据
      this.spanArr = []
      this.position = 0
      this.tableData.forEach((item, index) => {
        if (index === 0) {
          this.spanArr.push(1)
          this.position = 0
        } else {
          // inquiryCode 为需要合并查询的项
          if (this.tableData[index].inquiryCode === this.tableData[index - 1].inquiryCode) {
            this.spanArr[this.position] += 1
            this.spanArr.push(0)
          } else {
            this.spanArr.push(1)
            this.position = index
          }
        }
      })
    },
    objectSpanMethod({ row, column, rowIndex, columnIndex }) {
      if (columnIndex === 0 || columnIndex === 1 || columnIndex === 2 || columnIndex === 3 || columnIndex === 4 || columnIndex === 10 || columnIndex === 11 || columnIndex === 12 || columnIndex === 13) {
        const _row = this.spanArr[rowIndex]
        const _col = _row > 0 ? 1 : 0
        return {
          rowspan: _row,
          colspan: _col
        }
      }
    },
  }
}

    <el-card class="box-card">
      <el-table
        :data="tableData"
        border
        stripe
        style="width: 100% "
        @selection-change="handleSelectionChange"
      >
        <el-table-column type="selection" width="55" align="center"></el-table-column>
        <el-table-column prop="id" label="学号" align="center"></el-table-column>
        <el-table-column prop="name" label="姓名" align="center"></el-table-column>
        <el-table-column prop="sex" label="性别" align="center"></el-table-column>
        <el-table-column prop="college" label="学院" align="center"></el-table-column>
        <el-table-column label="操作" align="center">
          <template slot-scope="scope" class="active">
            <el-button @click="editData(scope.row)" type="primary" icon="el-icon-edit" circle></el-button>
            <el-button @click="removeData(scope.row.id)" type="danger" icon="el-icon-delete" circle></el-button>
          </template>
        </el-table-column>
      </el-table>
      <el-row :gutter="20">
        <el-col :span="6" :offset="12">
          <div class="block">
            <el-pagination
              background
              @current-change="handleCurrentChange"
              :current-page.sync="currentPage"
              :page-size="pageSize"
              layout="total, prev, next, jumper, pager"
              :total="total"
            ></el-pagination>
          </div>
        </el-col>
      </el-row>
    </el-card>

removeData(id) {
      //提示框，判断用户是否操作失误
      this.$confirm("此操作将永久删除此学生, 是否继续?", "警告", {
        confirmButtonText: "继续",
        cancelButtonText: "取消",
        type: "warning"
      })
        .then(() => {
          const data = { id }; //这里<=>data = {id:id}
          axiOS
            .post("URL", data)
            .then(response => {
              this.fetchdata(); //删除数据后重新获取数据
            })
            .catch(() => {
              this.$message({
                type:"warning",
                message:"请求失败，请检查网络设置"
              })
            });
        })
        .catch(() => {
          this.$message({
            type: "info",
            message: "已取消删除"
          });
        });
    }