element-ui合并行:span-method

 objectSpanMethod({ row, column, rowIndex, columnIndex }) {
       if (columnIndex === 0) {
         if (rowIndex % 2 === 0) {
           return {
             rowspan: 2,
             colspan: 1
           };
         } else {
           return {
             rowspan: 0,
             colspan: 0
           };
         }
       }
     }

 <el-table :data="tableData" :span-method="objectSpanMethod" border>

element-ui合并行或列的计算方法

element-ui table :span-method（行合并）