• 2022-06-07
    按类别查询图书的平均价格,以下语句正确的是()。(选择一项)
    A: selectavg(price),typefrombookgroupbytype
    B: selectcount(price),typefrombookgroupbyprice
    C: selectavg(price),typefrombookgroupbyprice
    D: selectcount(price),typefrombookgroupbytype
  • 举一反三