Quiz Discussion

‘AS’ clause is used in SQL for

• 1]

  Selection operation

• 2]

  Rename operation

• 3]

  Join operation

• 4]

  Projection operation

Views constructed from SQL SELECT statements that conform to the SQL-92 standard may not contain

• 1]

  GROUP BY

• 2]

  WHERE

• 3]

  ORDER BY

• 4]

  FROM

Count function in SQL returns the number of

• 1]

  Values

• 2]

  Distinct values

• 3]

  Groups

• 4]

  Columns

Which of the following is a valid SQL type?

• 1]

  CHARACTER

• 2]

  NUMERIC

• 3]

  FLOAT

• 4]

  All of the above

What is an advantage of placing computations in SQL views

• 1]

  To save users from having to write an expression

• 2]

  To ensure that the results are consistent

• 3]

  To accomplish both of the above

• 4]

  None of the above

Which one of the following is not true for a view

• 1]

  View is derived from other tables

• 2]

  View is a virtual table

• 3]

  A view definition is permanently stored as part of the database

• 4]

  View never contains derived columns

Which of the following is correct

• 1]

  a SQL query automatically eliminates duplicates

• 2]

  SQL permits attribute names to be repeated in the same relation

• 3]

  a SQL query will not work if there are no indexes on the relations

• 4]

  None of these

What SQL structure is used to limit column values of a table?

• 1]

  The LIMIT constraint

• 2]

  The CHECK constraint

• 3]

  The VALUE constraint

• 4]

  None of the above

Which of the following is a legal expression in SQL?

• 1]

  SELECT NULL FROM EMPLOYEE;

   

• 2]

  SELECT NAME FROM EMPLOYEE;

   

• 3]

  SELECT NAME FROM EMPLOYEE WHERE SALARY = NULL;

   

• 4]

  None of the above

   

To delete a particular column in a relation the command used is

• 1]

  UPDATE

• 2]

  DROP

• 3]

  ALTER

• 4]

  DELETE