element(table头部合并)_海北军_table合并头部

<el-table type="selection" :data="tableData" border>
  <el-table-column
    label="退款金额比例"
    header-align="center" align="center">
  </el-table-column>
  <el-table-column
    prop="signBill" label="签单"
    header-align="center" align="center">
    <el-table-column
      prop="signBill" :label="signBill"
      header-align="center" align="center">
    </el-table-column>
  </el-table-column>
  <el-table-column
    label="科目一"
    header-align="center" align="center">
    <el-table-column
      prop="subjectOne" :label="subjectOne"
      header-align="center" align="center">
    </el-table-column>
  </el-table-column>
  <el-table-column
    label="科目二"
    header-align="center" align="center">
    <el-table-column
      prop="subjectTwo" :label="subjectTwo"
      header-align="center" align="center">
    </el-table-column>
  </el-table-column>
  <el-table-column
    label="科目三"
    header-align="center" align="center">
    <el-table-column
      prop="subjectThree" :label="subjectThree"
      header-align="center" align="center">
    </el-table-column>
  </el-table-column>
  <el-table-column
    label="科目四"
    header-align="center" align="center">
    <el-table-column
      prop="subjectFour" :label="subjectFour"
      header-align="center" align="center">
    </el-table-column>
  </el-table-column>
</el-table><el-table type="selection" :data="tableData" bo