效果

前台

        <el-table
          v-loading="listLoading"
          :data="tableData"
          border
          tooltip-effect="dark"
          style="width: 100%">
          <el-table-column type="expand">
            <template slot-scope="props">
              <el-table
                ref="multipleTable"
                :data="props.row.charges"
                style="width: 100%"
                row-key="guid">
                <el-table-column
                  :column-key="guid"
                  fixed
                  align="center"
                  type="selection"/>
                <el-table-column
                  prop="startDate"
                  label="开始日期"/>
                <el-table-column
                  prop="endDate"
                  label="结束日期"/>
                .....................
              </el-table>
            </template>
          </el-table-column>
          <el-table-column
            prop="billNo"
            label="票据号"/>
           ............................
        </el-table>

弄完后有padding，需要改下样式

/deep/ .el-table__expanded-cell{
  padding-top: 0px;
  padding-right: 0px;
  padding-bottom: 0px;
  border-right-width: 0px;
  border-bottom-width: 0px;
}