OCP考题解析_007: 内联视图优化all或any操作符

本文探讨了SQL查询中使用ANY关键字的情况,并通过实例展示了如何将其转换为使用内联视图的形式以提高查询效率。
       个人的理解, 内联视图通常是指: 一个SQL查询的结果作为另一个查询的数据源, 一般在 From字句后面
       
       any表示数据集中的任何一个、相当于or
       x > any (select sal from emp where job='ANA')
       等价于:
       exists (select sal from emp where job='ANA' and x > sal)
       
       使用ALL和ANY的子查询总是可以用内嵌视图来代替,而且这个视图的性能要好的多,因为它利用了被连接表上的索引
       
       比如:any操作符
       

       需求:返回所有birthday > 出生于1985年之后的任何客户 的职员名称

select ename
from emp
where birthdate > any
        (select birthdate from customer where birthdate > '31-DEC-1985')


       上面的SQL语句可以优化为

select ename
from emp,(select min(birthdate) min_bday from customer where birthdate > '31-DEC-1985') in_line_view
where emp.birthdate > in_line_view.min_bday;


       OCP考题:

Q: 8 Click the Exhibit button and examine the data from the ORDERS and
CUSTOMERS tables.
Evaluate this SQL statement:

SELECT cust_id, ord_total
FROM orders
WHERE ord_total > ANY(SELECT ord_total
FROM orders
WHERE cust_id IN (SELECT cust_id
FROM customers
WHERE city LIKE
'New York'));

What is the result when the above query is executed?  


<6>[ 101.532908][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_pinctrl_set: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_pinctrl_set]+++pin:1, state:1. <6>[ 101.532908][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_pinctrl_set: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_pinctrl_set]+++pin:1, state:1. <6>[ 101.532908][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_pinctrl_set: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_pinctrl_set]+++pin:1, state:1. <6>[ 101.532920][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_pinctrl_set: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_pinctrl_set]flashlights_ocp8111 enter flash mode <6>[ 101.532920][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_pinctrl_set: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_pinctrl_set]flashlights_ocp8111 enter flash mode <6>[ 101.532920][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_pinctrl_set: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_pinctrl_set]flashlights_ocp8111 enter flash mode <6>[ 101.532920][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_pinctrl_set: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_pinctrl_set]flashlights_ocp8111 enter flash mode <3>[ 101.537951][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_enable: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_enable]flash enabled flag:1. <3>[ 101.537951][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_enable: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_enable]flash enabled flag:1. <3>[ 101.537951][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_enable: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_enable]flash enabled flag:1. <6>[ 101.619136][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_ioctl: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_ioctl]FLASH_IOC_SET_ONOFF(channel:0): 0 <6>[ 101.619136][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_ioctl: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_ioctl]FLASH_IOC_SET_ONOFF(channel:0): 0 <6>[ 101.619136][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_ioctl: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_ioctl]FLASH_IOC_SET_ONOFF(channel:0): 0 <3>[ 101.619163][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_disable: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_disable]Enter ocp8111_disable. <3>[ 101.619163][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_disable: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_disable]Enter ocp8111_disable. <3>[ 101.619163][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_disable: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_disable]Enter ocp8111_disable. <6>[ 101.619171][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_pinctrl_set: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_pinctrl_set]boardid_get = S98901AA1, TorchFlag = 0. <6>[ 101.619171][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_pinctrl_set: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_pinctrl_set]boardid_get = S98901AA1, TorchFlag = 0. <6>[ 101.619171][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_pinctrl_set: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_pinctrl_set]boardid_get = S98901AA1, TorchFlag = 0. <6>[ 101.619177][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_pinctrl_set: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_pinctrl_set]+++pin:1, state:0. <6>[ 101.619177][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_pinctrl_set: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_pinctrl_set]+++pin:1, state:0. <6>[ 101.619177][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_pinctrl_set: [name:flashlights_ocp8111&]flashLight-ocp8111[ocp8111_pinctrl_set]+++pin:1, state:0. <6>[ 101.619187][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_pinctrl_set: [name:flashlights_ocp8111&]flashlights_ocp8111 set PIN_MAIN GPIO LOW <6>[ 101.619187][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_pinctrl_set: [name:flashlights_ocp8111&]flashlights_ocp8111 set PIN_MAIN GPIO LOW <6>[ 101.619187][T703362] 3ATHREAD: flashlights_ocp8111: ocp8111_pinctrl_set: [name:flashlights_ocp8111&]flashlights_ocp8111 set PIN_MAIN GPIO LOW 这些打印中,有哪一条说明闪光灯进行打闪,说一下
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