CBSE Class 11 & 12 Computer Science and Informatics Practices Python Materials, Video Lecture

Structured Query Language (1 Mark Questions)

  1. None of the aboveWhich is the subset of SQL command used to manipulate Oracle Database Structures:
    • DDL(Data Definition Language)
    • DML (Data Manipulation Language)
    • Both
    • None of the above
  2. What is the difference between count(*) and count(<col>).
  3. "Pay" is a column name for the Pay of staff  in a table "Schools".
    The following SQL queries are used to find 
    the total number of paid employees:  
    i) SELECT count(*) FROM Schools;
    ii) SELECT count(Pay) FROM Schools;
    The outputs obtained are 40 and 39 in both the queries respectively.
    What is the reason behind different output?
  4. What is the use of COMMIT in sql ?
  5. What is the function of ALTER command?
  6. NULL value means :
    • 0 value
    • 1 value
    • None value
    • None of the above

No comments:

Post a Comment