Page 296 - PYTHON-12

(vi)
Pname Quantity Rate
Eraser 100 5
Copy 50 20
Pencil 20 20
Book 10 100
Pen 10 20
(b) Based on the Orders Table given above, write SQL query to display the minimum quantity, maximum
quantity and total quantity of Orders.
Ans. SELECT MIN(Quantity), MAX(Quantity), SUM(Quantity) FROM Orders;
(c) What is the difference between COUNT(*) and COUNT(Column Name)?
Ans. COUNT(*) includes the cells in the column containing NULL values.
COUNT(Column name) ignores the cells in the column containing NULL values.

UNSOLVED QUESTIONS

1. What is an Alternate Key?
2. What are views? How are they useful?
3. Define the following terms:
(a) Relation
(b) Tuple
(c) Attribute
(d) Domain
4. What do you understand by the terms candidate key and cardinality of a relation in a relational database?
5. What is SQL? What are different categories of commands available in SQL?
6. What is a database system? What is its need?
7. Differentiate between DDL and DML commands.
8. What is a datatype? Name some datatypes available in MySQL.
9. Differentiate between char and varchar datatypes.
10. Which operator concatenates two strings in a query result?
11. How would you calculate 13*15 in SQL?
12. Which keywords eliminate redundant data from a query?
13. Write SQL queries to perform the following based on the table PRODUCT having fields as (prod_id,
prod_name, quantity, unit_rate, price, city)
(i) Display those records from table PRODUCT where prod_id is more than 100.
(ii) List records from table PRODUCT where prod_name is ‘Almirah’.
(iii) List all those records whose price is between 200 and 500.
(iv) Display the product names whose price is less than the average of price.
14. Define the following terms:
(v) Show the total number of records in the table PRODUCT.
Computer Science with Python–XII 12.66 (ii) Data Inconsistency

(i) Database
(iii) Primary Key
(iv) Candidate Key
(v) Indexes