单项选择题
Given the following tables: CONTINENTS ID NAME COUNTRIES
1 Antarctica 0
2 Africa 53
3 Asia 47
4 Australia 14
5 Europe 43
6 North America 23
7 South America 12
REGION ID LOCATION 1 East 2 West
How many rows would be returned using the following statement? SELECT location FROM continents, region（）
A.2
B.7
C.9
D.14
相关考题
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单项选择题
Which of the following statements eliminates all but one of each set of duplicate rows in the DEPT column in the STAFF table?（）
A.SELECT UNIQUE dept FROM staff
B.SELECT DISTINCT dept FROM staff
C.SELECT (dept) UNIQUE FROM staff
D.SELECT (dept) DISTINCT FROM staff -
单项选择题
In which of the following situations should correlation names be used?（）
A.A table referenced in the FROM clause has no indexed column.
B.The table referenced in the FROM clause has more than 200 columns.
C.Two or more tables in the FROM clause have identical column names.
D.The FROM clause contains two or more tables in the SELECT statement. -
单项选择题
Consider the following table called EMPLOYEES: ID FIRSTNAME LASTNAME JOB LEVEL CLERK 3 If the following SQL statement is executed, how many rows will be deleted? DELETE FROM employees WHERE 1 = 1（）
A.0
B.1
C.3
D.6
