前言

Element的表格组件并没有给出明确的点击单个单元格进行的编辑的方案，我仔细阅读了官方的文档后，发现这个操作还是可以实现的。

实现原理

1. 利用Table组件的cell-click属性，可以获取当前点击的单元格列对应的Dom元素。
2. 清空所有的名为current-cell的class属性。
3. 为当前获取的单元格Dom动态添加名为current-cell的class属性。
4. 控制单元格的input标签的显示隐藏就能实现表格的编辑功能。

代码实现

<template>
  <div class="tableDiv">
    <el-table :data="tableData" highlight-current-row @cell-click="cellClick">
      <el-table-column
        v-for="(item, index) in tableColumn"
        :key="index"
        :prop="item.prop"
        :label="item.label"
        :width="item.width"
      >
        <template slot-scope="scope">
          <el-input
            v-if="item.edit"
            size="small"
            ref="tableInput"
            v-model="scope.row[item.prop]"
            @blur="removeClass"
            @change="handleEdit(item.prop, scope.$index, scope.row)"
          ></el-input>
          <span>{{ scope.row[item.prop] }}</span>
        </template>
        <el-table-column
          v-for="(itemchild, indexchild) in item.children"
          :key="indexchild"
          :prop="itemchild.prop"
          :label="itemchild.label"
          :width="itemchild.width"
        >
          <template slot-scope="scope">
            <el-input
              v-if="itemchild.edit"
              size="small"
              ref="tableInput"
              v-model="scope.row[itemchild.prop]"
              @blur="removeClass"
              @change="handleEdit(itemchild.prop, scope.$index, scope.row)"
            ></el-input>
            <span>{{ scope.row[itemchild.prop] }}</span>
          </template>
        </el-table-column>
      </el-table-column>
    </el-table>
  </div>
</template>

<script>
import { Column, tableData } from "./tableColumn";
export default {
  data() {
    return {
      tableData: tableData,
      tableColumn: Column
    };
  },
  methods: {
    handleEdit() {},
    cellClick(row, column, cell, event) {
      for(let i=0;i<document.getElementsByClassName('current-cell').length;i++){
        document.getElementsByClassName('current-cell')[i].classList.remove('current-cell');
      }
      cell.classList.add("current-cell");
    },
    removeClass(){
      document.getElementsByClassName('current-cell')[0].classList.remove('current-cell');
    }
  }
};
</script>
<style scoped>
.tableDiv .el-input {
  display: none;
}
.current-cell .el-input {
  display: block;
}
.current-cell .el-input + span {
  display: none;
}
</style>

tableColumn.js文件

const Column = [
    { label: '项目名称', prop: 'itemName', width: '300', key: '100' },
    { label: '项目编码', prop: 'itemCode', width: '150', key: '200' },
    { label: '单位', prop: 'compName', width: '150', key: '300', edit: true },
    {
        label: '费用', prop: '', width: '450', align: 'center', key: '400', children: [
            { label: '人工费', prop: 'staff', width: '150', key: '401', edit: true },
            { label: '资料费', prop: 'material', width: '150', key: '402', edit: true },
            { label: '场地费', prop: 'site', width: '150', key: '403' }
        ]
    }
];
const tableData = [
    { itemName: "北京水立方", itemCode: "1351157698", compName: "北京", staff: "100", material: "84547", site: "6544", sort: 1 },
    { itemName: "北京水立方", itemCode: "1351157698", compName: "北京", staff: "100", material: "84547", site: "6544", sort: 2 },
    { itemName: "北京水立方", itemCode: "1351157698", compName: "北京", staff: "100", material: "84547", site: "6544", sort: 3 },
    { itemName: "北京水立方", itemCode: "1351157698", compName: "北京", staff: "100", material: "84547", site: "6544", sort: 4 },
    { itemName: "北京水立方", itemCode: "1351157698", compName: "北京", staff: "100", material: "84547", site: "6544", sort: 5 },
    { itemName: "北京水立方", itemCode: "1351157698", compName: "北京", staff: "100", material: "84547", site: "6544", sort: 6 },
    { itemName: "北京水立方", itemCode: "1351157698", compName: "北京", staff: "100", material: "84547", site: "6544", sort: 7 },
    { itemName: "北京水立方", itemCode: "1351157698", compName: "北京", staff: "100", material: "84547", site: "6544", sort: 8 },
    { itemName: "北京水立方", itemCode: "1351157698", compName: "北京", staff: "100", material: "84547", site: "6544", sort: 9 },
    { itemName: "北京水立方", itemCode: "1351157698", compName: "北京", staff: "100", material: "84547", site: "6544", sort: 10 }
]
export {
    Column, tableData
}

注意：注意相应的样式不能少，非常重要！！！
页面效果：