Prerequisite – PL/SQL Introduction

In PL/SQL code groups of commands are arranged within a block. A block group related declarations or statements. In declare part, we declare variables and between begin and end part, we perform the operations.

**Problem :**

Write a script in PL/SQL to display all the prime numbers between any two positive whole numbers.

**Explanation :**

Here, all the prime numbers between any two numbers taken as input as the upper limit and the lower limit are returned.A prime number is a natural number greater than 1 that cannot be formed by multiplying two smaller natural numbers.

In this implementation, the number of divisors of a number that occurs between the two limits is counted which should be 2 (1 and the number itself). If the number of divisors is 2, then that number is returned.

For example, consider the number 5. It has only two divisors: 1 and the number 5 itself.

Hence, it is a prime number.

**Examples :**

Input: 10 20 Output: 11 13 17 19 Input: 20 30 Output: 23 29

**Below is the implementation :**

` ` `DECLARE` `--the upper limit and the lower limit are taken as user inputs.` ` ` `low number(2);` ` ` `high number(2);` ` ` `n number(2);` ` ` `m number(2);` ` ` `c number(20);` `BEGIN` ` ` `dbms_output.put_line('Enter the lower and higher limit:');` ` ` `low:=&low;` ` ` `high:=&high;` `--The main operation happens in this loop` ` ` `for n IN low.. high ` ` ` `loop` ` ` `c:=0;` ` ` `for m IN 1.. n` ` ` `loop ` ` ` `if mod(n, m)=0 then` ` ` `c:=c+1;` ` ` `end if;` ` ` `end loop;` `--the number of divisors for each number in the range is counted and then checked.` ` ` `if c<=2 then ` ` ` `dbms_output.put_line(n||'\n');` ` ` `end if;` ` ` `end loop;` ` ` `END;` |

**Output :**

Input: Enter the lower and higher limit:1 10 Output: 2 3 5 7

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