Q19. Select a primary producer from the list
A: Sharks
B: Urchins
C: Seagrass
D: Worms
E: Birds
A: Sharks
B: Urchins
C: Seagrass
D: Worms
E: Birds
举一反三
- 使用教学（STC）数据库，与如下查询语句等价的是（ ）。 SELECT *FROM Student WHERE Sdept = 'CS' EXCEPT SELECT * FROM Student WHERE Sage <= 19; A: SELECT * FROM Student WHERE Sdept = 'CS' AND Sage > 19 B: SELECT * FROM Student WHERE Sdept = 'CS' AND Sage <= 19 C: SELECT * FROM Student WHERE Sdept = 'CS' OR Sage <= 19 D: SELECT * FROM Student WHERE Sdept = 'CS' OR Sage > 19
- The following is a synonym of autotrophs A: Primary producer B: Consumer C: Heterotroph D: Predator
- Acanthocephalans are commonly called ( ). A: roundworms B: blood worms C: flatworms D: probosis worms E: spiny-headed worms
- The nematodes are commonly known as( ). A: flatworms B: segmented worms C: roundworms D: beard worms E: tongue worms
- create table t（id int not null, a int default 0, b int default 0, c int default 0, primary key（id）, key idx_a_b（a, b））;下面语句能够利用到索引的是（） A: select b from t where a=10; B: select * from t where a=10 and id=100; C: select * from t where a=10 and b＞100; D: select * from t where a＞10 and b ＜ 100; E: select * from t order by b limit 10;