el-table 在第一行添加合计行和操作按钮

<el-table
  size="small"
  stripe
  style="width: 100%"
  class="table_info"
  v-loading="loading"
  :data="list"
  show-summary>
  <el-table-column
    label="标题"
    prop="Title"
    min-width="2">
  </el-table-column>
  <el-table-column
    label="1数量"
    prop="Num1"
    min-width="2">
  </el-table-column>
  <el-table-column
    label="2数量"
    prop="Num2"
    min-width="2">
  </el-table-column>
  <el-table-column
    label="3数量"
    prop="Num3"
    min-width="2">
  </el-table-column>
  <el-table-column
    label="4数量"
    prop="Num4"
    min-width="2">
  </el-table-column>
  <el-table-column
    label="操作"
    width="300">
    <template slot-scope="scope">
      <div style="line-height: 1; font-size: 0;">
        <el-button size="mini" @click="这里写单击方法">查看</el-button>
      </div>
    </template>
  </el-table-column>
</el-table>

// 合计行设置
showSummariesPosition () {
  // 合计行显示在表头
  let table = document.querySelector('.el-table')
  let footer = document.querySelector('.el-table__footer-wrapper')
  let body = document.querySelector('.el-table__body-wrapper')
  table.removeChild(footer)
  table.insertBefore(footer, body)
  // 在合计行的最后一列添加按钮
  let html = table.querySelectorAll('td')[5].querySelector('.cell')
  html.innerHTML = "<el-button size='mini' style='padding: 7px 15px;font-size:12px;border-radius:3px;display: inline-block;display: inline-block;line-height: 1;white-space: nowrap;cursor: pointer;background: #fff;border: 1px solid #dcdfe6;color: #606266;-webkit-appearance: none;text-align: center;box-sizing: border-box;outline: 0;margin: 0;transition: .1s;font-weight: 500;'>查看</el-button>"
  html.onclick = () => {
    this.toAllDetails()
  }
},

mounted () {
  this.$nextTick(() => {
    this.showSummariesPosition()
  })
},