HackerRank: [SQL Alternative Queries] (3/3) PRINT PRIME NUMBERS | declare, set, while, if, exists, substring in ms-sql

HackerRank: [SQL Alternative Queries] (3/3) PRINT PRIME NUMBERS | declare, set, while, if, exists, substring in ms-sql
I started studying SQL from a very famous site - HackerRank. Here I will try to provide multiple approaches & solutions to the same problem. It will help you learn and understand SQL in a better way.

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SQL Problem Statement:

Write a query to print all prime numbers less than or equal to 1000. Print your result on a single line, and use the ampersand (&) character as your separator (instead of a space).

For example, the output for all prime numbers <=10 would be:


Solution-1: (MS-SQL Query):

DECLARE @table TABLE (PrimeNumber INT)

SET @final = ''

DECLARE @counter INT
SET @counter = 2

WHILE @counter <= 1000
FROM @table
WHERE @counter % primenumber = 0)
SELECT @counter

SET @final = @final + Cast(@counter AS VARCHAR(20)) + '&'

SET @counter = @counter + 1

SELECT Substring(@final, 0, Len(@final));

  • The DECLARE statement is used to declare a variable in SQL and its value is set to NULL.

  • SET is for initializing the variable you declared previously, and you cannot SET the variable until you DECLARE it.

  • SQL WHILE loop is used to execute the SQL statement(s) repeatedly until the specified condition result turn out to be false.

  • The EXISTS operator is used to test for the existence of any record in a subquery. The EXISTS operator returns TRUE if the subquery returns one or more records.

Explanation (Flow Chart):

Expected Output:


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-Akshay P Daga
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