單項選擇題

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

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單項選擇題

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.

單項選擇題

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

Which of the following statements eliminates all but one of each set of duplicate rows in the DEPT column in the STAFF table?（）

你可能感興趣的試題

In which of the following situations should correlation names be used?（）

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（）

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（）