注意点：

1. <el-table> 中 加:summary-method="getSummaries"

2.  <el-table-column> 中要加 prop 

    // 房间号的合计去掉
    getSummaries (param) {
      const { columns, data } = param
      const sums = []
      columns.forEach((column, index) => {
        if (index === 0) {
          sums[index] = '总计'
        } else if (index === 5 || index === 6) {
          const values = data.map(item => Number(item[column.property]))
          if (!values.every(value => isNaN(value))) {
            sums[index] = values.reduce((prev, curr) => {
              const value = Number(curr)
              if (!isNaN(value)) {
                return prev + curr
              } else {
                return prev
              }
            }, 0)
          } else {
            sums[index] = 'N/A'
          }
        } else {
          sums[index] = '--'
        }
      })
      return sums
    }

效果图