ichcc/test-tasks

test-tasks

Task 1 Calculate Sum of elements from the matrix main diagonal

Input Format

The first line contains the integer, the size of the matrix (N). The next lines contains the matrix elements separated by a space.

Output Format

Print one line: Sum of elements from the matrix main diagonal.

Constraints

2 < N < 100

Sample Input 0

3
1 2 3
4 5 6
7 8 9

Sample Output 0

15

Task 2. Find the average of the marks obtained by the particular student

Input Format

The first line contains the integer, the number of students (N). The next lines contains the name and marks obtained by that student separated by a space. The final line contains the name of a particular student previously listed.

Constraints

2 < N < 100
0 < Marks < 100

Output Format

Print one line: The average of the marks obtained by the particular student correct to 2 decimal places.

Sample Input 0

3
Krishna 67 68 69
Arjun 70 98 63
Malika 52 56 60
Malika

Sample Output 0

56.00

Explanation 0

Marks for Malika are {52 56 60} whose average is (52+56+60)/3 is 56.

Sample Input 1

2
Harsh 25 26.5 28
Anurag 26 28 30
Harsh

Sample Output 1

26.50

Task 3. SQL Task 1

Given the following tables:

sql> SELECT * FROM runners;
+----+--------------+
| id | name         |
+----+--------------+
|  1 | John Doe     |
|  2 | Jane Doe     |
|  3 | Alice Jones  |
|  4 | Bobby Louis  |
|  5 | Lisa Romero  |
+----+--------------+

+----+----------------+-----------+
| id | event          | winner_id |
+----+----------------+-----------+
|  1 | 100 meter dash |  2        |
|  2 | 500 meter dash |  3        |
|  3 | cross-country  |  2        |
|  4 | triathalon     |  NULL     |

+----+----------------+-----------+

What will be the result of the query below?

SELECT * FROM runners WHERE id NOT IN (SELECT winner_id FROM races)

Explain your answer and also provide an alternative version of this query that will avoid the issue that it exposes.

Task 4 SQL Task 2

Assume a schema of Emp ( Id, Name, DeptId ) , Dept ( Id, Name). If there are 10 records in the Emp table and 5 records in the Dept table, how many rows will be displayed in the result of the following SQL query:

Select * From Emp, Dept

Explain your answer.

Task 5. SQL Task 3

Write a query how do you copy data from one table to another table?

Task 6. SQL Task 4

You have a table: create table test (name VARCHAR(20), email VARCHAR(20));

How to find a duplicate record?

1. Duplicate records with one field
2. Duplicate records with more than one field (both name and email).