OCP-1Z0-051-V9.02-137题
来源:互联网 发布:网页音频抓取工具 mac 编辑:程序博客网 时间:2024/04/29 15:44
137. View the Exhibits and examine PRODUCTS and SALES tables.
You issue the following query to display product name and the number of times the product has been
sold:
SQL>SELECT p.prod_name, i.item_cnt
FROM (SELECT prod_id, COUNT(*) item_cnt
FROM sales
GROUP BY prod_id) i RIGHT OUTER JOIN products p
ON i.prod_id = p.prod_id;
What happens when the above statement is executed?
A. The statement executes successfully and produces the required output.
B. The statement produces an error because ITEM_CNT cannot be displayed in the outer query.
C. The statement produces an error because a subquery in the FROM clause and outer-joins cannot be
used together.
D. The statement produces an error because the GROUP BY clause cannot be used in a subquery in the
FROM clause.
Answer: A
答案解析:
通过子查询,查询出产品卖出去的次数。
在通过右连接产品表,显示出所有产品。
实验验证:
sh@TEST0924> SELECT p.prod_name, i.item_cnt
2 FROM (SELECT prod_id, COUNT(*) item_cnt FROM sales GROUP BY prod_id)
3 i RIGHT OUTER JOIN products p
4 ON i.prod_id = p.prod_id;
PROD_NAME ITEM_CNT
-------------------------------------------------- ----------
Envoy External Keyboard 3441
SIMM- 8MB PCMCIAII card 19557
Mouse Pad 29282
External 6X CD-ROM 13043
...
72 rows selected.
- OCP-1Z0-051-V9.02-137题
- OCP-1Z0-051-V9.02-1题
- OCP-1Z0-051-V9.02-1题
- OCP-1Z0-051-V9.02-1题
- OCP-1Z0-051-V9.02-11题
- OCP-1Z0-051-V9.02-12题
- OCP-1Z0-051-V9.02-14题
- OCP-1Z0-051-V9.02-15题
- OCP-1Z0-051-V9.02-17题
- OCP-1Z0-051-V9.02-18题
- OCP-1Z0-051-V9.02-21题
- OCP-1Z0-051-V9.02-118题
- OCP-1Z0-051-V9.02-120题
- OCP-1Z0-051-V9.02-32题
- OCP-1Z0-051-V9.02-33题
- OCP-1Z0-051-V9.02-93题
- OCP-1Z0-051-V9.02-94题
- OCP-1Z0-051-V9.02-95题
- 逐象素的Spot Light的实现
- df命令使用
- 代码脏乱的“蛀牙”效应
- 关于实时 Ambient Occlusion 一点猜想
- 汽车喷漆效果的实现
- OCP-1Z0-051-V9.02-137题
- TP-LINK WR703N 刷OpenWrt并设置pppoe联网、安装LUCI、添加新用户、挂载USB设备、配置ftp服务、借由transmission实现脱机下载
- CI(3) model CRUD
- Partitioned Indexes
- 华为软件研发面试题1
- TP-LINK WR703N 刷OpenWrt并设置pppoe联网、安装LUCI、添加新用户、挂载USB设备、配置ftp服务、借由transmission实现脱机下载(续)
- C语言中的结构及用法
- Unity 3D 光照贴图快速入门 Lightmapping Quickstart
- qt中mysql的编译问题