现有书目表book，包含字段：价格price(float)，类别type(char);现在查询各个
A. 的平均价格、类别名称，以下语句正确的是（）。
B. selectavg(price),typefrombookgroupbytype
C. selectcount(price),typefrombookgroupbyprice
D. selectavg(price),typefrombookgroupbyprice
E. selectcount(price),typefrombookgroupbytype
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现有订单表orders，包含用户信息userid,产品信息productid,以下（）语句能够返回至少被订购过两回的productid?（选择一项）
A. selectproductidfromorderswherecount(productid)>1
B. selectproductidfromorderswheremax(productid)>1
C. selectproductidfromorderswherehavingcount(productid)>1groupbyproductid_
D. selectproductidfromordersgroupbyproductidhavingcount(productid)>1
查询student表中的所有非空email信息,以下语句正确的是（）。（选择一项）
A. Selectemailfromstudentwhereemail!=null
B. Selectemailfromstudentwhereemailnotisnull
C. Selectemailfromstudentwhereemail<>null
D. Selectemailfromstudentwhereemailisnotnull
类别名称，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
Please fill in the blanks according to hints given in brackets.In the country of Colombia, burning “Mr. Old Year” is a New Year’s （1.习俗）. It requires the （2.全家参与）. It is a lot of fun; they create a big stuffed male doll that （3.代表旧年）. Then they （4.塞入）the doll with a large choice of different materials. Sometimes they put some little （5.烟火）in it to make it more exciting at the time they burn it.
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