支持多级表头设置吗？

[LovePsychedelico]

类似
excel_columns = [
{ label: '产品号', prop: 'product_code' },
{ label: '价格',
children:[
{label: '工价', prop: 'cost_total'},
{label: '工时', prop: 'working_hours_cost_total'},
]
},
]