單項選擇題

The EMP table contains these columns:
LAST_NAME VARCHAR2 (25)
SALARY NUMBER (6,2)
DEPARTMENT_ID NUMBER (6)
You need to display the employees who have not been assigned to any department. You write the SELECT statement:
SELECT LAST_NAME, SALARY, DEPARTMENT_ID
FROM EMP
WHERE DEPARTMENT_ID = NULL;
What is true about this SQL statement ?（）

A.The SQL statement displays the desired results.
B.The column in the WHERE clause should be changed to display the desired results.
C.The operator in the WHERE clause should be changed to display the desired results.
D.The WHERE clause should be changed to use an outer join to display the desired results.

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多項選擇題

In which three cases would you use the USING clause?（）

A.You want to create a nonequijoin.
B.The tables to be joined have multiple NULL columns.
C.The tables to be joined have columns of the same name and different data types.
D.The tables to be joined have columns with the same name and compatible data types.
E.You want to use a NATURAL join, but you want to restrict the number of columns in the join condition.

多項選擇題

Which two tasks can you perform using only the TO_CHAR function? （）

A.convert 10 to 'TEN'
B.convert '10' to 10
C.convert 10 to '10'
D.convert 'TEN' to 10
E.convert a date to a character expression
F.convert a character expression to a date

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你可能感興趣的試題

In which three cases would you use the USING clause?（）

Which two tasks can you perform using only the TO_CHAR function? （）