huangliang0703的专栏

89. View the Exhibit and examine the description of the DEPARTMENTS and EMPLOYEES tables.To retrieve data for all the employees for their EMPLOYEE_ID, FIRST_NAME, and DEPARTMENT NAME,the following

文章来自：http://m.blog.youkuaiyun.com/blog/linwaterbin/8631039You can set the default session time zone with the ORA_SDTZ environment variable. When users retrieve TIMESTAMP WITH LOCAL TIME ZONE dat

以employees表为例进行说明：一、如果只是统计不同部门不同岗位的平均工资，直接使用group by 子句：  1  select department_id ,job_id,avg(salary)  2  from employees  3  group by (department_id ,job_id)SQL> /DEPARTMENT_ID JOB

View the Exhibit and examine the structure of ORDERS and ORDER_ITEMS tables.ORDER_ID is the primary key in the ORDERS table. It is also the foreign key in the ORDER_ITEMS table where in it is crea

133. Which three statements are true? (Choose three.) A. Only one LONG column can be used per table. B. A TIMESTAMP data type column stores only time values with fractional seconds. C. The BLO

52、You have a read-only tablespace on read-only media. You want to perform. a media recovery on the existing data files, but using a backup control file. The backup control file indicates that the s

130. Which three statements are true regarding single-row functions? (Choose three.) A. They can accept only one argument. B. They can be nested up to only two levels. C. They can return multi

129. Which three statements are true regarding group functions?(Choose three.) A. They can be used on columns or expressions. B. They can be passed as an argument to another group function.C.

74. View the Exhibit and examine the structure of the ORDER_ITEMS and ORDERS tables. You are asked to retrieve the ORDER_ID, PRODUCT_ID, and total price (UNIT_PRICE multiplied by QUANTITY), wher

SQL> create user a identified by a default tablespace users;User created.SQL> create user b identified by a default tablespace users;User created.SQL> create user c identified by a default

39. View the Exhibit and examine the description of the PRODUCT_INFORMATION table.Which SQL statement would retrieve(检索) from the table the number of products having LIST_PRICE as NULL?比较null值用is

生产部门有以下的需求，但是类似的表有64 张，t_cmp_type_paymentrecord1 （后缀1到64），本来想写成 64 个这样的sql ，然后用union all进行拼接，但感觉这样拼接也累，跟同事请教，使用了另一种方法。 select * from t_cmp_type_paymentrecord1 where status=3 and paymenttype=0 an