data.data.forEach(element => {
   this.thead.push({
   品名: element.品名,
   面取数: element.面取数,
   LOTNO: element.LOT
   });

<el-table-column
 v-for="(item,index) in thead"
 :prop="item.LOTNO"
 :key="index"
 align="center"
 width="180"
>
 <template slot="header">
 <tr>
  <td>{{item.品名}}</td>
 </tr>
 <tr>
  <td>{{item.面取数}}</td>
 </tr>
 <tr>
  <td @click="querylot(item.LOTNO)">
  <el-link>{{item.LOTNO}}</el-link>
  </td>
 </tr>
 </template>
</el-table-column>

for (let index1 = 3;index1 < Object.keys(结果_data[0]).length;index1++) {
  let newmap = new Map();
  let datakey = Object.keys(结果_data[0])[index1];
  newmap.set("mode", datakey); //取出每个数组对象的键值
  for (let index2 = 0; index2 < 结果_data_length; index2++) {
   let datavalue = 结果_data[index2][Object.keys(结果_data[0])[index1]];
   if (datakey == "投入日期") {
   datavalue = datavalue.slice(0, 10);
   }
   newmap.set(
   结果_data[index2][Object.keys(结果_data[index2])[0]],datavalue);//获得这个键对应的所有的值
  }

 <el-table :data="tableData" span-method="objectSpanMethod">

objectSpanMethod({ row, column, rowIndex, columnIndex }) {
  if (columnIndex === 0) {
  if (rowIndex % this.tableData.length === 0) {
   return {
   rowspan: this.tableData.length,
   colspan: 1
   };
  } else {
   return {
   rowspan: 0,
   colspan: 0
   };
  }
  }
 }

import FileSaver from "file-saver";
import XLSX from "xlsx";
 output() {
  alert(1);
  let wb = XLSX.utils.table_to_book(document.querySelector("#mytable")); //mytable为表格的id名
  let wbout = XLSX.write(wb, {
  bookType: "xlsx",
  bookSST: true,
  type: "array"
  });
  try {
  FileSaver.saveAs(
   new Blob([wbout], { type: "application/octet-stream" }),
   "sheet.xlsx"
  );
  } catch (e) {
  if (typeof console !== "undefined") console.log(e, wbout);
  }
  return wbout;
 }