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7. Rectangle Validation (Easy)
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Problem Statement

Table: Rectangle
This table stores the dimensions of rectangles. Each row contains the lengths of four sides of a rectangle.

+---------------+------+
| Column Name   | Type |
+---------------+------+
| a             | int  |
| b             | int  |
| c             | int  |
| d             | int  |
+---------------+------+
(a, b, c, d) is the primary key for this table.
Each row of this table contains the lengths of four sides of a rectangle.

Determine for each set of four line segments whether they can form a rectangle. A set of line segments can form a rectangle if opposite sides are equal.

Return the result table in any order.

Example

Input:

Rectangle table:
+----+----+----+----+
| a  | b  | c  | d  |
+----+----+----+----+
| 15 | 10 | 15 | 10 |
| 15 | 10 | 15 | 20 |
+----+----+----+----+

Output:

+----+----+----+----+-----------+
| a  | b  | c  | d  | rectangle |
+----+----+----+----+-----------+
| 15 | 10 | 15 | 10 | Yes       |
| 15 | 10 | 15 | 20 | No        |
+----+----+----+----+-----------+

In this example, the first set of sides (15, 10, 15, 10) can form a rectangle because the opposite sides are equal. The second set of sides (15, 10, 15, 20) cannot form a rectangle because not all opposite sides are equal.

Try It YourSelf

MYSQL
MYSQL
. . . .

Solution

To solve this problem, we need to check each row in the Rectangle table to determine if the given sides can form a rectangle based on the condition that opposite sides must be equal.

  1. Check Opposite Sides: Verify if sides (a, c) and (b, d) are equal for each row.
  2. Return Result: Based on the equality of opposite sides, return 'Yes' if the sides can form a rectangle, otherwise return 'No'.

SQL Query

SELECT a, b, c, d,
       CASE
           WHEN a = c AND b = d THEN 'Yes'
           ELSE 'No'
       END as rectangle
FROM Rectangle;

Step by Step Approach

Step 1: Check Opposite Sides

Check if opposite sides are equal for each row in the table.

SELECT a, b, c, d,
       (a = c AND b = d) as is_rectangle
FROM Rectangle

Output After Step 1:

+----+----+----+----+--------------+
| a  | b  | c  | d  | is_rectangle |
+----+----+----+----+--------------+
| 15 | 10 | 15 | 10 | 1            |
| 15 | 10 | 15 | 20 | 0            |
+----+----+----+----+--------------+

Step 2: Return Result

Based on the equality check, return 'Yes' if the sides can form a rectangle, otherwise return 'No'.

SELECT a, b, c, d,
       CASE
           WHEN a = c AND b = d THEN 'Yes'
           ELSE 'No'
       END as rectangle
FROM Rectangle

Final Output:

+----+----+----+----+-----------+
| a  | b  | c  | d  | rectangle |
+----+----+----+----+-----------+
| 15 | 10 | 15 | 10 | Yes       |
| 15 | 10 | 15 | 20 | No        |
+----+----+----+----+-----------+

.....

.....

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