效果图下：

<template>
  <div class="container">
    <el-table
      ref="multipleTable"
      id="multipleTable"
      :data="person.tableData"
      @cell-mouse-enter="cellEnter"
      @cell-mouse-leave="cellLeave"
      @selection-change="handleSelectionChange"
    >
      <el-table-column type="selection" width="50" align="center">
        <template #default="{ row, $index }">
          <!-- 复选框显示：通过移入事件添加id判断 || 已经勾选了的复选框 -->
          <div
            v-if="
              person.columnCheckedId == row.id || person.checkedList[$index]
            "
          >
            <el-checkbox
              v-model="person.checkedList[$index]"
            ></el-checkbox>
          </div>
          <!-- 序号显示：通过下标显示 -->
          <span v-else>{{ $index + 1 }}</span>
        </template>
      </el-table-column>
      <el-table-column prop="name" label="姓名"> </el-table-column>
      <el-table-column prop="age" label="性别"> </el-table-column>
      <el-table-column prop="six" label="年龄"> </el-table-column>
    </el-table>
  </div>
</template>

<script setup>
import { computed, reactive, ref } from "vue";
const person = reactive({
  columnCheckedId: "",
  tableData: [
    { name: "123", id: 1, age: 10, six: "男" },
    { name: "123", id: 2, age: 20, six: "男" },
    { name: "123", id: 3, age: 330, six: "女" },
  ],
  multipleSelection: [], //全选
  checkedList: [], //table多选选中数据
});
// 全选
function handleSelectionChange(val) {
  person.multipleSelection = val;
  if (person.multipleSelection.length == person.tableData.length) {
    person.multipleSelection.forEach((item, index) => {
      person.checkedList[index] = true;
      console.log(person.checkedList[index]);
    });
  }
  if (person.multipleSelection.length == 0) {
    person.checkedList = [];
  }
}
//移入当前行
function cellEnter(row) {
  person.columnCheckedId = row.id;
}
// 移出当前行
function cellLeave(row) {
  person.columnCheckedId = "";
}
</script>