
SQL查询5.sql
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简介:
本文件包含五个高级SQL查询示例,旨在提高数据检索和操作效率。每个查询都针对特定的数据分析任务,适用于数据库管理和优化场景。
/**----从KuChun表选择所有列select * from KuChun
--从Sell表选择所有列select * from Sell
--按SellID,ProductType分组并求每个组合的总销售数量(Sumd)及其类型与标识(select sum(SellNum)as Sumd,SellID,ProductType from Sell group by SellID,ProductTypes)
--KuChun和Sell表联接,计算各产品类型的库存量及累计销量,并按ShopID排序(from KuChun t1 left join (select SellID, sum(sellnum)as snum,ProductType from Sell group by SellID,ProductType)t2on t1.ShopID=t2.SellID and t1.ProductType=t2.ProductTypeorder by t1.ShopID)
--查询每个店铺的库存量以及对应的产品类型,同时计算各产品类型的累计销售数量(SELECT T1.SHOPID, T1.PRODUCTTYPE, T1.KNUM, (select ISNULL(sum(t2.sellnum),0) from Sell t2 where t2.sellid = t1.shopid and t2.producttype= t1.productType) sumsell FROM KuChun T1 order by t1.shopid)
--查询每个店铺的库存量以及对应的产品类型,同时计算各产品类型的累计销售数量(select T1.SHOPID, T1.PRODUCTTYPE, T1.KNUM, ISNULL(sum(t2.sellnum),0) sellnumfrom KuChun t1left join Sell t2 on t2.sellid = t1.shopid and t2.producttype= t1.productTypegroup by T1.SHOPID, T1.PRODUCTTYPE, T1.KNUMorder by t1.shopid)
--查询各店铺的库存总量以及对应的产品类型,并计算销售数量(select T1.SHOPID, sum(T1.KNUM) as TotalStock ,T2.ProductName from KuChun AS T1 JOIN Product AS T2 ON T1.PRODUCTTYPE = T2.ID GROUP BY T1.ShopId,T2.ProductName)
--查询学生分数情况,以及教师姓名和课程名称(select s.s_name, c.c_name, t.t_name, a.s_score from Student as s join Score as a on s.s_id=a.s_id join Course as c on a.c_id=c.c_id left join Teacher as t on t.t_id = c.t_id)
--查询选修“张三”老师课程的学生中,成绩最高的学生信息(select * from (select st.*, a.s_score, row_number() over(order by a.s_score desc) as num from Student st left join Score a on st.s_id=a.s_id left join Course c on a.c_id=c.c_id left join Teacher t on t.t_id = c.t_id where t.t_name=张三)tt where tt.num=1)
--查询每门课程的学生人数(select count(a.s_id),c.c_name from Score a left join Course as c on a.c_id=c.c_id group by c.c_name)*/
以上SQL语句主要用于数据库中进行数据的检索、计算和分析。
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