公司SQL考核及小结(Oracle)
一.数据库初始化脚本:
Create TABLE HAND_CUSTOMERS ( CUSTOMERS_NO Varchar2(10), CUSTOMERS_NAME Varchar2(30), CUSTOMERS_GENDER Varchar2(3), CUSTOMERS_BIRTH_DATE Date ); comment on TABLE HAND_CUSTOMERS is '顾客表'; comment on COLUMN HAND_CUSTOMERS.CUSTOMERS_NO is '客户编号'; comment on COLUMN HAND_CUSTOMERS.CUSTOMERS_NAME is '客户名称'; comment on COLUMN HAND_CUSTOMERS.CUSTOMERS_GENDER is '客户性别'; comment on COLUMN HAND_CUSTOMERS.CUSTOMERS_BIRTH_DATE is '客户出生日期'; Create TABLE HAND_SELLERS ( SELLER_NO Varchar2(10), SELLER_NAME Varchar2(30), MANAGER_NO Varchar2(10) ); comment on TABLE HAND_SELLERS is '销售员表'; comment on COLUMN HAND_SELLERS.SELLER_NO is '销售员编码'; comment on COLUMN HAND_SELLERS.SELLER_NAME is '销售员名称'; comment on COLUMN HAND_SELLERS.MANAGER_NO is '销售员经理'; --- Create Table HAND_GOODS ( GOODS_NO Varchar2(10), GOODS_NAME Varchar2(30), GOODS_PRICE Number ); comment on table HAND_GOODS is '商品表'; comment on column HAND_GOODS.GOODS_NO is '商品编码'; comment on column HAND_GOODS.GOODS_NAME is '商品名称'; comment on column HAND_GOODS.GOODS_PRICE is '商品单价'; ---- Create Table HAND_SALES_RECORDS ( CUSTOMERS_NO Varchar2(10), SELLER_NO Varchar2(10), GOODS_NO Varchar2(10), SALES_QUANTY Number, SALES_DATE Date ); comment on table HAND_SALES_RECORDS is '销售记录表'; comment on column HAND_SALES_RECORDS.CUSTOMERS_NO is '客户编号'; comment on column HAND_SALES_RECORDS.SELLER_NO is '销售员编码'; comment on column HAND_SALES_RECORDS.GOODS_NO is '商品编码'; comment on column HAND_SALES_RECORDS.SALES_QUANTY is '销售数量'; comment on column HAND_SALES_RECORDS.SALES_DATE is '销售记录'; ------ INSERT INTO HAND_CUSTOMERS(CUSTOMERS_NO, CUSTOMERS_NAME, CUSTOMERS_GENDER, CUSTOMERS_BIRTH_DATE) values ('C001', '张三', '男', TO_DATE('1990/1/1','YYYY/MM/DD')); INSERT INTO HAND_CUSTOMERS(CUSTOMERS_NO, CUSTOMERS_NAME, CUSTOMERS_GENDER, CUSTOMERS_BIRTH_DATE) values ('C002', '李四', '男', TO_DATE('1994/3/2','YYYY-MM-DD')); INSERT INTO HAND_CUSTOMERS(CUSTOMERS_NO, CUSTOMERS_NAME, CUSTOMERS_GENDER, CUSTOMERS_BIRTH_DATE) values ('C003', '吴鹏', '男', TO_DATE('1996/2/19','YYYY-MM-DD')); INSERT INTO HAND_CUSTOMERS(CUSTOMERS_NO, CUSTOMERS_NAME, CUSTOMERS_GENDER, CUSTOMERS_BIRTH_DATE) values ('C004', '琴沁', '女', TO_DATE('1997/1/4','YYYY-MM-DD')); INSERT INTO HAND_CUSTOMERS(CUSTOMERS_NO, CUSTOMERS_NAME, CUSTOMERS_GENDER, CUSTOMERS_BIRTH_DATE) values ('C005', '王丽', '女', TO_DATE('1998/1/5','YYYY-MM-DD')); INSERT INTO HAND_CUSTOMERS(CUSTOMERS_NO, CUSTOMERS_NAME, CUSTOMERS_GENDER, CUSTOMERS_BIRTH_DATE) values ('C006', '李波', '男', TO_DATE('1998/4/6','YYYY-MM-DD')); INSERT INTO HAND_CUSTOMERS(CUSTOMERS_NO, CUSTOMERS_NAME, CUSTOMERS_GENDER, CUSTOMERS_BIRTH_DATE) values ('C007', '刘玉', '女', TO_DATE('1998/7/7','YYYY-MM-DD')); INSERT INTO HAND_CUSTOMERS(CUSTOMERS_NO, CUSTOMERS_NAME, CUSTOMERS_GENDER, CUSTOMERS_BIRTH_DATE) values ('C008', '萧蓉', '男', TO_DATE('1998/8/21','YYYY-MM-DD')); INSERT INTO HAND_CUSTOMERS(CUSTOMERS_NO, CUSTOMERS_NAME, CUSTOMERS_GENDER, CUSTOMERS_BIRTH_DATE) values ('C009', '陈萧晓', '女', TO_DATE('1994/12/1','YYYY-MM-DD')); INSERT INTO HAND_CUSTOMERS(CUSTOMERS_NO, CUSTOMERS_NAME, CUSTOMERS_GENDER, CUSTOMERS_BIRTH_DATE) values ('C010', '陈美', '女', TO_DATE('1999/10/10','YYYY-MM-DD')); ------ INSERT INTO HAND_SELLERS(SELLER_NO, SELLER_NAME, MANAGER_NO ) values ('X001', '销售A', ''); INSERT INTO HAND_SELLERS(SELLER_NO, SELLER_NAME, MANAGER_NO ) values ('X002', '销售B', 'X001'); INSERT INTO HAND_SELLERS(SELLER_NO, SELLER_NAME, MANAGER_NO ) values ('X003', '销售C', 'X001'); INSERT INTO HAND_SELLERS(SELLER_NO, SELLER_NAME, MANAGER_NO ) values ('X004', '销售D', 'X003'); INSERT INTO HAND_SELLERS(SELLER_NO, SELLER_NAME, MANAGER_NO ) values ('X005', '销售E', 'X003'); ------- INSERT INTO HAND_GOODS(GOODS_NO, GOODS_NAME, GOODS_PRICE) values ('GOODS001', '商品A', 120); INSERT INTO HAND_GOODS(GOODS_NO, GOODS_NAME, GOODS_PRICE) values ('GOODS002', '商品B', 159); INSERT INTO HAND_GOODS(GOODS_NO, GOODS_NAME, GOODS_PRICE) values ('GOODS003', '商品C', 349); INSERT INTO HAND_GOODS(GOODS_NO, GOODS_NAME, GOODS_PRICE) values ('GOODS004', '商品D', 256); INSERT INTO HAND_GOODS(GOODS_NO, GOODS_NAME, GOODS_PRICE) values ('GOODS005', '商品E', 412); INSERT INTO HAND_GOODS(GOODS_NO, GOODS_NAME, GOODS_PRICE) values ('GOODS006', '商品F', 342); INSERT INTO HAND_GOODS(GOODS_NO, GOODS_NAME, GOODS_PRICE) values ('GOODS007', '商品G', 234); INSERT INTO HAND_GOODS(GOODS_NO, GOODS_NAME, GOODS_PRICE) values ('GOODS008', '商品H', 776); INSERT INTO HAND_GOODS(GOODS_NO, GOODS_NAME, GOODS_PRICE) values ('GOODS009', '商品I', 123); INSERT INTO HAND_GOODS(GOODS_NO, GOODS_NAME, GOODS_PRICE) values ('GOODS010', '商品J', null); --- INSERT INTO HAND_SALES_RECORDS(CUSTOMERS_NO, SELLER_NO, GOODS_NO, SALES_QUANTY, SALES_DATE) values ('C001', 'X001', 'GOODS001', 32, TO_DATE('2019/6/8','YYYY-MM-DD')); INSERT INTO HAND_SALES_RECORDS(CUSTOMERS_NO, SELLER_NO, GOODS_NO, SALES_QUANTY, SALES_DATE) values ('C002', 'X002', 'GOODS001', 39, TO_DATE('2019/6/18','YYYY-MM-DD')); INSERT INTO HAND_SALES_RECORDS(CUSTOMERS_NO, SELLER_NO, GOODS_NO, SALES_QUANTY, SALES_DATE) values ('C002', 'X003', 'GOODS003', 20, TO_DATE('2019/6/19','YYYY-MM-DD')); INSERT INTO HAND_SALES_RECORDS(CUSTOMERS_NO, SELLER_NO, GOODS_NO, SALES_QUANTY, SALES_DATE) values ('C004', 'X004', 'GOODS004', 4, TO_DATE('2019/6/11','YYYY-MM-DD')); INSERT INTO HAND_SALES_RECORDS(CUSTOMERS_NO, SELLER_NO, GOODS_NO, SALES_QUANTY, SALES_DATE) values ('C005', 'X005', 'GOODS005', 60, TO_DATE('2019/6/12','YYYY-MM-DD')); INSERT INTO HAND_SALES_RECORDS(CUSTOMERS_NO, SELLER_NO, GOODS_NO, SALES_QUANTY, SALES_DATE) values ('C006', 'X003', 'GOODS006', 30, TO_DATE('2019/6/13','YYYY-MM-DD')); INSERT INTO HAND_SALES_RECORDS(CUSTOMERS_NO, SELLER_NO, GOODS_NO, SALES_QUANTY, SALES_DATE) values ('C006', 'X002', 'GOODS007', 36, TO_DATE('2019/6/14','YYYY-MM-DD')); INSERT INTO HAND_SALES_RECORDS(CUSTOMERS_NO, SELLER_NO, GOODS_NO, SALES_QUANTY, SALES_DATE) values ('C004', 'X001', 'GOODS006', 40, TO_DATE('2019/6/15','YYYY-MM-DD')); INSERT INTO HAND_SALES_RECORDS(CUSTOMERS_NO, SELLER_NO, GOODS_NO, SALES_QUANTY, SALES_DATE) values ('C001', 'X003', 'GOODS001', 10, TO_DATE('2019/6/19','YYYY-MM-DD')); INSERT INTO HAND_SALES_RECORDS(CUSTOMERS_NO, SELLER_NO, GOODS_NO, SALES_QUANTY, SALES_DATE) values ('C002', 'X002', 'GOODS002', 41, TO_DATE('2019/4/11','YYYY-MM-DD')); INSERT INTO HAND_SALES_RECORDS(CUSTOMERS_NO, SELLER_NO, GOODS_NO, SALES_QUANTY, SALES_DATE) values ('C003', 'X003', 'GOODS003', 30, TO_DATE('2019/3/12','YYYY-MM-DD')); INSERT INTO HAND_SALES_RECORDS(CUSTOMERS_NO, SELLER_NO, GOODS_NO, SALES_QUANTY, SALES_DATE) values ('C003', 'X003', 'GOODS004', 60, TO_DATE('2019/6/11','YYYY-MM-DD')); INSERT INTO HAND_SALES_RECORDS(CUSTOMERS_NO, SELLER_NO, GOODS_NO, SALES_QUANTY, SALES_DATE) values ('C003', 'X002', 'GOODS005', 76, TO_DATE('2019/6/19','YYYY-MM-DD')); INSERT INTO HAND_SALES_RECORDS(CUSTOMERS_NO, SELLER_NO, GOODS_NO, SALES_QUANTY, SALES_DATE) values ('C003', 'X001', 'GOODS006', 68, TO_DATE('2019/6/25','YYYY-MM-DD')); INSERT INTO HAND_SALES_RECORDS(CUSTOMERS_NO, SELLER_NO, GOODS_NO, SALES_QUANTY, SALES_DATE) values ('C004', 'X005', 'GOODS005', 32, TO_DATE('2018/6/18','YYYY-MM-DD')); COMMIT;
二.Sql语句题:
1.条件:查询没有卖出过“商品B”的销售人员信息 显示:销售员编码,销售员名称,管理员编码,管理员名称 :
--1 SELECT hs.seller_no ,hs.seller_name ,hsm.seller_no ,hsm.seller_name FROM hand_sellers hs ,hand_sellers hsm WHERE hs.manager_no = hsm.seller_no(+) AND NOT EXISTS (SELECT 1 FROM hand_sales_records hsr ,hand_goods hg WHERE hsr.goods_no = hg.goods_no AND hg.goods_name = '商品B' AND hsr.seller_no = hs.seller_no); --2 SELECT hs.seller_no ,hs.seller_name ,hsm.seller_no ,hsm.seller_name FROM hand_sellers hs ,hand_sellers hsm WHERE hs.manager_no = hsm.seller_no(+) AND hs.seller_no NOT IN (SELECT hsr.seller_no FROM hand_sales_records hsr ,hand_goods hg WHERE hsr.goods_no = hg.goods_no AND hg.goods_name = '商品B'); --考点:外连接、NOT EXISTS 和 NOT IN 的用法及区别
小结:
1.in和exists:
in是把外表和内表作hash连接(会用到外表上的索引),而exists是对外表作loop循环(用到内表上的索引),每次loop循环再对内表进行查询,如果查询的两个表大小相当,那么用in和exists差别不大;如果两个表中一个较小一个较大,则子查询表大的用exists,子查询表小的用in;
2.not in和not exists:
not in 逻辑上不完全等同于not exists。使用not in时,如果子查询中返回的任意一条记录含有空值,则查询将不返回任何记录。如果子查询字段有非空限制,这时可以使用not in,并且可以通过提示让它用hasg_aj或merge_aj连接。如果查询语句使用了not in,那么对内外表都进行全表扫描,没有用到索引;而not exists的子查询依然能用到表上的索引。所以无论哪个表大,用not exists都比not in 要快。
参照:https://blog.csdn.net/baidu_37107022/article/details/77278381
2.条件:查询6 月中旬,所有顾客的消费情况。显示:顾客编号、顾客名称、顾客性别、销售商品、销售时间、销售数量排序:消费数量从高到低。说明:如果没有消费记录,销售商品、销售时间、销售数量留空
--1 SELECT hc.customers_no ,hc.customers_name ,hc.customers_gender ,hg.goods_name ,hsr.sales_date ,hsr.sales_quanty FROM hand_sales_records hsr ,hand_goods hg ,hand_customers hc WHERE hsr.goods_no = hg.goods_no(+) AND hsr.customers_no(+) = hc.customers_no --AND hsr.sales_date(+) BETWEEN to_date('2019-06-10', 'yyyy-mm-dd') AND to_date('2019-06-20', 'yyyy-mm-dd') AND to_char(hsr.sales_date(+), 'MM') = '06' AND to_char(hsr.sales_date(+), 'DD') BETWEEN 10 AND 20 ORDER BY hsr.sales_quanty DESC; --2 SELECT hc.customers_no ,hc.customers_name ,hc.customers_gender ,hg.goods_name ,hsr.sales_date ,hsr.sales_quanty FROM hand_sales_records hsr ,hand_goods hg ,hand_customers hc WHERE hsr.goods_no = hg.goods_no AND hsr.customers_no = hc.customers_no AND hsr.sales_date BETWEEN to_date('2019-06-10', 'yyyy-mm-dd') AND to_date('2019-06-20', 'yyyy-mm-dd') ORDER BY hsr.sales_quanty DESC; --考点:外连接,日期函数
小结:
1.查两表关联列相等的数据用内连接。
2.Col_L是Col_R的子集时用右外连接。
3.Col_R是Col_L的子集时用左外连接。
4.Col_R和Col_L彼此有交集但彼此互不为子集时候用全外。
5.求差操作的时候用联合查询。
3.条件:查询购买记录3条以上的顾客信息。 显示:顾客编号、顾客名称、顾客出生日期 :
--1 SELECT hc.customers_no ,hc.customers_name ,hc.customers_birth_date FROM hand_customers hc WHERE hc.customers_no IN (SELECT hsr.customers_no FROM hand_sales_records hsr GROUP BY hsr.customers_no HAVING COUNT(1) > 3); --2 SELECT hc.customers_no ,hc.customers_name ,hc.customers_birth_date FROM hand_customers hc WHERE EXISTS (SELECT 1 FROM hand_sales_records hsr WHERE hc.customers_no = hsr.customers_no GROUP BY hsr.customers_no HAVING COUNT(1) > 3);
小结:
where是筛选行,having是筛选已经查询出来的字段。
4.条件:查询顾客中姓氏为"张""李""刘"的顾客信息显示:顾客编号、顾客名称、顾客,出生日期。排序:顾客出生日期从近到远。说明:正则表达式。除正则表达式以外的其他方式:
--正则 SELECT hc.customers_no ,hc.customers_name ,hc.customers_birth_date FROM hand_customers hc WHERE regexp_like(hc.customers_name, '^张.*|^李.*|^刘.*'); --Like SELECT hc.customers_no ,hc.customers_name ,hc.customers_birth_date FROM hand_customers hc WHERE (hc.customers_name LIKE '张%' OR hc.customers_name LIKE '李%' OR hc.customers_name LIKE '刘%');
小结:
还可以使用substring()等函数提取第一个字符看是否在要查找的条件里面
5.条件:查询商品信息,当商品价格在100-199 时 打9 折,在200-299 时打8 折,在300 以上打7 折。显示:商品编码、商品名称、商品打折前单价、商品打折后单价:
SELECT hg.goods_no ,hg.goods_name ,hg.goods_price ,CASE WHEN hg.goods_price BETWEEN 100 AND 199 THEN hg.goods_price * 0.9 WHEN hg.goods_price BETWEEN 200 AND 299 THEN hg.goods_price * 0.8 WHEN hg.goods_price >= 300 THEN hg.goods_price * 0.7 ELSE hg.goods_price END changed_goods_price FROM hand_goods hg
6.查询生日在当前月份的顾客信息。显示:顾客名称,顾客生日,顾客购买总数量。排序:顾客生日:
SELECT hc.customers_no ,hc.customers_name ,hc.customers_birth_date ,(select sum(hsr.sales_quanty) from hand_sales_records hsr where hsr.customers_no = hc.customers_no ) FROM hand_customers hc WHERE to_char(hc.customers_birth_date,'MM') =to_char(sysdate,'MM') ; --考点: 日期函数,子查询
小结:
就考察了子查询,以及to_char函数转换为字符串的函数,注意对应的to_date将字符串转换为日期
7.条件:查询商品单价在100 到199 之间的商品信息。显示:商品名称、单价。说明:单价为空的商品也进行显示:
--1 SELECT hg.goods_no ,hg.goods_name ,hg.goods_price FROM hand_goods hg where nvl( hg.goods_price,100) BETWEEN 100 AND 199; --2 SELECT hg.goods_no ,hg.goods_name ,hg.goods_price FROM hand_goods hg WHERE hg.goods_price BETWEEN 100 AND 199 OR hg.goods_price IS NULL
小结:
就考察了between..and的用法(包括前面,不包括后面),以及nvl()函数,注意nvl(expr1,expr2)和nvl2(expr1,expr2,expr3)的区别
8.条件:查询所有销售员的销售总数量。显示:销售员编码、销售员名称、销售数量、销售名次。排序:按照销售数量进行倒序。说明:如果有销售数量相同的,销售名次如下输出。销售汇总数量60,60,57 名次 1,1,3:
SELECT hs.seller_no ,hs.seller_name ,SUM(sr.sales_quanty) sales_quanty ,RANK() OVER(ORDER BY SUM(sr.sales_quanty) DESC) rank_level FROM hand_sales_records sr ,hand_sellers hs WHERE sr.seller_no(+) = hs.seller_no GROUP BY hs.seller_no ,hs.seller_name
小结:
注意开窗函数【分析函数提供一系列比较高级的SQL功能。分析函数时建立在数据窗口(over在一定的数据库范 围进行数据分析),在一定的数据范围进行排序、汇总】over(partition by...order by...)其中partition by表示以什么分组,如果没有则使用group by的分组,rank()【用于返回结果集的分区内每行的排名,行的排名是相关行之前的排名数加一,如果排序的标准相同,则排名也相同】和dense_rank()【与rank函数类似,dense_rank函数在生成序号时是连续的,而rank函数生成的序号有可能不连续】,row_number()【为查询出来的每一行记录生成一个序号,依次排序且不会重复】。还值得注意的是MySQL应该是在8.0之后才有开窗函数(查询资料),可以使用自连接比较数量排序。
9.条件:查询销售数量高于商品“商品A”的最大销售数量的所有销售记录。显示: 商品名称、销售员名称、顾客名称、销售数量、销售日期。 with 不计入(with 和子查询算一种方法):
--sn1 SELECT g.goods_name ,hs.seller_name ,c.customers_name ,sr.sales_quanty ,sr.sales_date FROM hand_goods g ,hand_sales_records sr ,hand_sellers hs ,hand_customers c WHERE 1 = 1 AND sr.seller_no = hs.seller_no(+) AND sr.goods_no = g.goods_no(+) AND sr.customers_no = c.customers_no AND sr.sales_quanty > (SELECT MAX(sr1.sales_quanty) FROM hand_sales_records sr1 ,hand_goods g1 WHERE sr1.goods_no = g1.goods_no AND g1.goods_name = '商品A'); --sn2 SELECT g.goods_name ,hs.seller_name ,c.customers_name ,sr.sales_quanty ,sr.sales_date FROM hand_goods g ,hand_sales_records sr ,hand_sellers hs ,hand_customers c WHERE 1 = 1 AND sr.seller_no = hs.seller_no(+) AND sr.goods_no = g.goods_no(+) AND sr.customers_no = c.customers_no AND sr.sales_quanty > ALL (SELECT sr1.sales_quanty FROM hand_sales_records sr1 ,hand_goods g1 WHERE sr1.goods_no = g1.goods_no AND g1.goods_name = '商品A'); --sn3 SELECT g.goods_name ,hs.seller_name ,c.customers_name ,sr.sales_quanty ,sr.sales_date FROM hand_goods g ,hand_sales_records sr ,hand_sellers hs ,hand_customers c WHERE 1 = 1 AND sr.seller_no = hs.seller_no(+) AND sr.goods_no = g.goods_no(+) AND sr.customers_no = c.customers_no AND EXISTS (SELECT 1 FROM hand_sales_records sr1 ,hand_goods g1 WHERE sr1.goods_no = g1.goods_no AND g1.goods_name = '商品A' AND sr.sales_quanty > sr1.sales_quanty);
小结:
考核外连接语法,Oracle使用+可以简化外连接SQL(left/right join),主要是找准关系,需要返回哪边的所有行,然后就是ALL(注意all和any的区别,如题all是大于查询出的所有,即比结果中的最大的还大,而any只要是其中任意一个就行),EXISTS(exists和in的区别,exists是遍历外表在查询,而in1是遍历查询出的内表结果)的用法。
10.条件:分别根据 商品+销售员+顾客、商品+销售员 、销售员、总销售数量的维度俩统计销售数量。显示:商品、销售员、顾客、汇总销售数量:
SELECT g.goods_name ,hs.seller_name ,c.customers_name ,SUM(sr.sales_quanty) FROM hand_goods g ,hand_sales_records sr ,hand_sellers hs ,hand_customers c WHERE 1 = 1 AND sr.seller_no = hs.seller_no(+) AND sr.goods_no = g.goods_no(+) AND sr.customers_no = c.customers_no GROUP BY ROLLUP(g.goods_name, hs.seller_name, c.customers_name)
小结:
注ROLLUP和CUBE的区别。使用ROLLUP产生常规分组汇总行 以及分组小计,Rollup 后面跟了n个字段,就将进行n+1次分组,从右到左每次减少一个字段进行分组;然后进行 union 【n+1次分组】。CUBE是后面跟了n个字段,就将进行2的N次方的分组运算,然后进行。MySQL中使用with rollup/cube。
11.条件:查询商品销售数量总数量为前三的商品。显示:商品编号,商品名称,销售数量。排序:按照销售数量进行排序。说明:如果商品销售数量的前4 名为 100,80,67,67 则4 条记录都显示:
SELECT g.goods_no ,g.goods_name ,t.total_quanty FROM hand_goods g ,(SELECT sr.goods_no ,SUM(sr.sales_quanty) total_quanty ,rank() over(ORDER BY SUM(sr.sales_quanty) DESC) rank_level FROM hand_sales_records sr WHERE 1 = 1 GROUP BY sr.goods_no) t WHERE t.goods_no = g.goods_no AND t.rank_level <= 3 ORDER BY t.total_quanty DESC
小结:
考察开窗函数以及rank()的使用(如题如果使用的分组的条件total_quanty,如果这个值相同,那么排名也相同)。
12.a.创建一个表HAND_GOODS_XXXXX 包含HAND_GOODS 表里金额大于200 的商品记录。b.将HAND_GOODS_XXXXX 的单价更新为原价的80%。c.将 HAND_GOODS 表里的记录合并至HAND_GOODS_XXXXX,通过商品编码进行匹配,如果表HAND_GOODS_XXXXX 中不存在记录,进行新建,如果存在记录则更新HAND_GOODS_XXXXX 的商品单价为HAND_GOODS 中的商品单价:
--a. CREATE TABLE HAND_GOODS_25305 AS SELECT * FROM hand_goods g WHERE g.goods_price > 200 --b. UPDATE HAND_GOODS_25305 SET goods_price = goods_price * 0.8 --c. MERGE INTO hand_goods_25305 g_new USING hand_goods g ON (g.goods_no = g_new.goods_no) WHEN MATCHED THEN UPDATE SET g_new.goods_price = g.goods_price WHEN NOT MATCHED THEN INSERT VALUES (g.goods_no ,g.goods_name ,g.goods_price);
小结:
考察创建,更新表,以及批量插入。
13.条件:查询购买商品数量总计最多的顾客信息。显示:顾客编号,顾客名称,购买商品数量:
WITH tab_sum AS (SELECT sr.customers_no ,SUM(sr.sales_quanty) total_quanty FROM hand_sales_records sr WHERE 1 = 1 GROUP BY sr.customers_no) SELECT t.customers_no, c.customers_name, t.total_quanty FROM tab_sum t, hand_customers c WHERE c.customers_no = t.customers_no AND t.total_quanty = ( SELECT MAX(total_quanty) FROM tab_sum)
小结:
使用子查询问,及with方便在后面多次使用则可以简化SQL并适当提高性能 。