--(1)用子查询查询员工“张小娟”所做的订单信息。

SELECT *

FROMorder_masterWHERE saler_no =(SELECTemployee_noFROMemployeeWHERE employee_name = '张小娟');--(2)查询没有订购商品的且在北京地区的客户编号，客户名称和邮政编码，并按邮政编码降序排序。

SELECTcustomer_no, customer_name, zipFROMcustomer xWHERE address = '北京市'

AND NOT EXISTS(SELECT *

FROMorder_master yWHERE x.customer_no =y.customer_no

)ORDER BY zip DESC;--(3)查询订购了“32M DRAM”商品的订单编号，订货数量和订货单价。

SELECTorder_no, quantity, priceFROMorder_detailWHERE product_no =(SELECTproduct_noFROMproductWHERE product_name = '32M DRAM');--(4)查询与员工编号“E2008005”在同一个部门的员工编号，姓名，性别，所属部门。

SELECTemployee_no, employee_name, sex, departmentFROMemployeeWHERE department =(SELECTdepartmentFROMemployeeWHERE employee_no = 'E2008005');--(5)查询既订购了P2005001商品，又订购了P2007002商品的客户编号，订单编号和订单金额

SELECTcustomer_no, order_no, order_sumFROMorder_master xWHERE EXISTS(SELECT *

FROMorder_detail yWHERE x.order_no =y.order_noAND product_no = 'P2005001')AND EXISTS(SELECT *

FROMorder_detail zWHERE x.order_no =z.order_noAND product_no = 'P2007002');--NOT EXISTS VS. NOT IN 写两个然后比较性能--(6)查询没有订购“52倍速光驱”或“17寸显示器”的客户编号，客户名称。

SELECTcustomer_no, customer_nameFROMcustomerWHERE customer_no NOT IN(SELECTcustomer_noFROMorder_masterWHERE order_no IN(SELECTorder_noFROMorder_detailWHERE product_no IN(SELECTproduct_noFROMproductWHERE product_name IN ('52倍速光驱', '17寸显示器')

)

)

);--ORDER BY VS. ALL VS MIN MAX--(7)查询订单金额最高的订单编号，客户姓名，销售员名称和相应的订单金额。

SELECTorder_no

, (SELECTcustomer_nameFROMcustomer yWHERE y.customer_no =x.customer_no

)AScustomer_name

, (SELECTemployee_nameFROMemployeeWHERE employee_no =saler_no

)ASemployee_name, order_sumFROMorder_master xORDER BY order_sum DESCLIMIT1;--IN 与 = 以及 OR--(8)查询订购了“52倍速光驱”商品的订购数量，订购平均价和订购总金额。

SELECT SUM(quantity), AVG(price)

, (SELECTorder_sumFROMorder_master yWHERE y.order_no =x.order_no

)ASorder_sumFROMorder_detail xWHERE product_no =(SELECTproduct_noFROMproductWHERE product_name = '52倍速光驱');--BETWEEN 2 AND 4--(9)查询订购了“52倍速光驱”商品且订货数量界于2~4之间的订单编号，订货数量和订货金额。

SELECTorder_no, quantity, priceFROMorder_detailWHERE product_no =(SELECTproduct_noFROMproductWHERE product_name = '52倍速光驱')AND quantity BETWEEN 2 AND 4;--GROUP BY--(10)在订单主表中查询每个业务员的订单数量

SELECT saler_no, COUNT(*) ASorder_numFROMorder_masterGROUP BYsaler_no;--COUNT(*) VS. COUNT(id) 任何性能对比都是基于特定 的存储引擎！--(11)统计在业务科工作且在1973年或1967年出生的员工人数和平均工资。

SELECT COUNT(employee_no) AS employee_num, AVG(salary)FROMemployeeWHERE department = '业务科'

AND YEAR(birthday) IN (1973, 1967);--(12)在订单明细表中统计每种商品的销售数量和金额，并按销售金额的升序排序输出。

SELECT product_no, SUM(quantity) ASquantity

,SUM(quantity * price) AStotalFROMorder_detailGROUP BYproduct_noORDER BYtotal;--(13)统计客户号为“C20050001”的客户的订单数，订货总额和平均订货金额

SELECT COUNT(*), SUM(order_sum)

,AVG(order_sum)FROMorder_masterWHERE customer_no = 'C2005001';--(14)统计每个客户的订单数，订货总额和平均订货金额。

SELECT customer_no, COUNT(*), SUM(order_sum)

,AVG(order_sum)FROMorder_masterGROUP BYcustomer_no;--(15)查询订单中至少包含3种(含3种)以上商品的订单编号及订购次数，且订购的商品数量在3件(含3件)以上。

SELECT order_no, COUNT(*)FROMorder_detailGROUP BYorder_noHAVING COUNT(DISTINCT product_no) >= 3

AND SUM(quantity) >= 3;--(16)查找订购了“32M DRAM”的商品的客户编号，客户名称，订货总数量和订货总金额。

SELECTcustomer_no

, (SELECTcustomer_nameFROMcustomer yWHERE y.customer_no =x.customer_no

)AScustomer_name

, (SELECT SUM(quantity)FROMorder_detail zWHERE z.order_no =x.order_no

)AStotal_quantity, order_sumFROMorder_master xWHERE order_no IN(SELECTorder_noFROMorder_detailWHERE product_no =(SELECTproduct_noFROMproductWHERE product_name = '32M DRAM')

);--(17)查询每个客户订购的商品编号，商品所属类别，商品数量及订货金额，结果显示客户名称，商品所属类别，商品数量及订货金额，并按客户编号升序和按订货金额的降序排序输出。

SELECT(SELECTcustomer_nameFROMcustomer nWHERE n.customer_no =m.customer_no

)AScustomer_name, product_class, quantity, priceFROM(SELECT(SELECTcustomer_noFROMorder_master xWHERE x.order_no =z.order_no

)AScustomer_no

, (SELECTproduct_classFROMproduct yWHERE y.product_no =z.product_no

)ASproduct_class, quantity, priceFROMorder_detail z

) mORDER BY customer_no, price DESC;--(18)按商品类别查询每类商品的订货平均单价在280元(含280元)以上的订货总数量，订货平均单价和订货总金额。

SELECT product_class, SUM(quantity), AVG(price)

,SUM(quantity *price)FROMorder_detail xLEFT JOIN product y ON x.product_no =y.product_noGROUP BYproduct_classHAVING AVG(price) >= 280;--(19)查找至少有2次销售的业务员名称和销售日期。

SELECT(SELECTemployee_nameFROMemployeeWHERE employee_no =saler_no

)ASemployee_name, order_dateFROMorder_master xWHERE x.saler_no IN(SELECTy.saler_noFROMorder_master yGROUP BYsaler_noHAVING COUNT(*) >= 2)ORDER BYsaler_no;--(20)查询销售金额最大的客户名称和总货款额

SELECT(SELECTcustomer_nameFROMcustomer yWHERE y.customer_no =x.customer_no

)AS customer_name, SUM(order_sum) AS sum

FROMorder_master xGROUP BYcustomer_noORDER BY sum DESCLIMIT1;--(21)查找销售总额小于5000元的销售员编号，姓名和销售额

SELECT x.employee_no, employee_name, SUM(order_sum)FROMemployee xLEFT JOIN order_master y ON x.employee_no =y.saler_noGROUP BYemployee_noHAVING SUM(order_sum) < 5000

OR SUM(order_sum) IS NULL;--(22)查找至少订购了3种商品的客户编号，客户名称，商品编号，商品名称，数量和金额。

SELECTe.customer_no, e.customer_name, r.product_no, r.product_name, quantity

, priceFROMorder_detail qLEFT JOIN order_master w ON w.order_no =q.order_noLEFT JOIN customer e ON e.customer_no =w.customer_noLEFT JOIN product r ON r.product_no =q.product_noWHERE q.order_no IN(SELECTt.order_noFROMorder_detail tGROUP BYt.order_noHAVING COUNT(*) >= 3)ORDER BYw.customer_no;--待修改，剪掉冗余中间表、无用列，用 EXISTS 重写--(23)查找同时订购了商品为“P2007002”和商品编号为“P2007001”的商品的客户编号，客户姓名，商品编号，商品名称和销售数量，按客户编号排序输出。

SELECTa.customer_no, a.customer_name, e.product_no, e.product_name, d.quantityFROMcustomer aLEFT JOIN order_master s ON a.customer_no =s.customer_noLEFT JOIN order_detail d ON s.order_no =d.order_noLEFT JOIN product e ON e.product_no =d.product_noWHERE a.customer_no IN(SELECTcustomer_noFROM(SELECTx.customer_no, x.customer_name, m.product_no, m.product_name, quantityFROMcustomer xLEFT JOIN order_master y ON x.customer_no =y.customer_noLEFT JOIN order_detail z ON z.order_no =y.order_noLEFT JOIN product m ON m.product_no =z.product_noWHERE m.product_no ="P2007001"GROUP BYx.customer_noUNION ALL

SELECTx.customer_no, x.customer_name, m.product_no, m.product_name, quantityFROMcustomer xLEFT JOIN order_master y ON x.customer_no =y.customer_noLEFT JOIN order_detail z ON z.order_no =y.order_noLEFT JOIN product m ON m.product_no =z.product_noWHERE m.product_no ="P2007002"GROUP BYx.customer_no

) pGROUP BYp.customer_noHAVING COUNT(*) >= 2)AND e.product_no IN("P2007001", "P2007002")ORDER BYa.customer_no;--(24)计算每一商品每月的销售金额总和，并将结果首先按销售月份然后按订货金额降序排序输出。

SELECT MONTH(order_date) AS month, x.product_no, product_name

,SUM(quantity * price) AStotoalFROMproduct xLEFT JOIN order_detail y ON x.product_no =y.product_noLEFT JOIN order_master z ON z.order_no =y.order_noGROUP BY MONTH(order_date), x.product_noORDER BY MONTH(order_date), totoal DESC;--(25)查询订购了“键盘”商品的客户姓名，订货数量和订货日期

SELECT(SELECTcustomer_nameFROMcustomer zWHERE z.customer_no =y.customer_no

)AScustomer_name, quantity, order_dateFROMorder_detail xLEFT JOIN order_master y ON x.order_no =y.order_noWHERE product_no =(SELECTproduct_noFROMproductWHERE product_name ="键盘"

);--(26)查询每月订购“键盘”商品的客户名称。

SELECT(SELECTcustomer_nameFROMcustomer zWHERE z.customer_no =y.customer_no

)AS customer_name, MONTH(order_date) AS month

FROMorder_detail xLEFT JOIN order_master y ON x.order_no =y.order_noWHERE product_no =(SELECTproduct_noFROMproductWHERE product_name ="键盘"

)ORDER BYorder_date;--(27)查询至少销售了5种商品的销售员编号，姓名，商品名称，数量及相应的单价，并按销售员编号排序输出。

SELECTemployee_no, employee_name, product_name, quantity, priceFROMemployee xLEFT JOIN order_master y ON x.employee_no =y.saler_noLEFT JOIN order_detail z ON z.order_no =y.order_noLEFT JOIN product m ON m.product_no =z.product_noWHERE(SELECT COUNT(DISTINCTproduct_no)FROMorder_master wLEFT JOIN order_detail e ON w.order_no =e.order_noWHERE w.saler_no =x.employee_no

)>= 5

ORDER BYemployee_no;--(28)查询没有订购商品的客户编号和客户名称。

SELECTcustomer_no, customer_nameFROMcustomer xWHERE NOT EXISTS(SELECT *

FROMorder_master yWHERE y.customer_no =x.customer_no

)