检查约束中，要求价格大于20，表达式为（）。
A: …… check (price >20)
B: …… check (price <30)
C: …… check (price between 20 and 30)
D: 都不是
A: …… check (price >20)
B: …… check (price <30)
C: …… check (price between 20 and 30)
D: 都不是
A
举一反三
- They sent me a ___________ for 1000 yuan. A: money B: cost C: check D: price
- 已经定义常量#define PRICE 30 则，下列语句使用常量正确的是（ ）。 A: PRICE = 20; B: int c=3;PRICE=c; C: int c=PRICE; D: PRICE++；
- 查询图书价格在30到50之间的图书名、作者和出版社,其中的查询条件表达式为（） A: where price>;=30 AND price<;=50 B: where price>;=30 OR price<;=50 C: where priceBETWEEN 30 AND 50 D: where priceBETWEEN50 AND 30
- 使用SQL语句将表s中字段price的值大于30的记录删除，正确的命令是（ ）。 A.DELETE FROM S FOR price>30 B.DELETE FROM sWHERE price>30 C.DELETE S FOR price>30 D.DELETE S WHERE price>30
- Before you buy an expensive item, or a service, do check the price and _______ is on offer. A: what B: which C: that D: this
内容
- 0
确保两次启动之间的时间至少间隔 30 秒。 A: Make sure that the time between starts is a minimum of 30 seconds. B: Check that 30 seconds have elapsed between starts. C: Check that 30 seconds have timed between starts.
- 1
分析以下SQL 命令: SELECT price FROM inventory WHERE price BETWEEN 1 AND 50 AND (price IN(55, 30, 95); 命令执行后的输出结果是：（） A: 55 B: 30 C: 95 D: NULL
- 2
If a 15% increase in price for a good results in a 20% decrease in quantity demanded, the price elasticity of demand is
- 3
在 SQL 语句中，与 BETWEEN 20 AND 30 等价的表达式是 ( )。 A: X>=20 AND X<30 B: X>20 AND X<30 C: X>20 AND X<=30 D: X>=20 AND X<=30
- 4
在SQL语句中，与BETWEEN 20 AND30等价的表达式是（ ）。 A: X>;=20 AND X<;30 B: X>;20 AND X<;30 C: X>;20 AND X<;=30 D: X>;=20 AND X<;=30