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  1. Prepare
  2. SQL
  3. Alternative Queries
  4. Print Prime Numbers
  5. Discussions

Print Prime Numbers

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1356 Discussions

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  • kofio7611
     + 0 comments

    i've not yet learnt cte can someone help with a basic sql code. i wrote this but it incorrect

    SELECT GROUP_CONCAT(num SEPARATOR '&') AS primes FROM ( SELECT n.num FROM numbers n WHERE n.num <= 100 AND n.num > 1 AND NOT EXISTS ( SELECT 1 FROM numbers d WHERE d.num > 1 AND d.num < n.num AND n.num % d.num = 0 ) ) AS prime_list;

  • rom_adv
     + 0 comments
    WITH RECURSIVE candidates AS (
    SELECT 4 AS i
    UNION ALL
    SELECT i + 1 FROM candidates WHERE i < 1000
),
divisors AS (
    SELECT 2 AS d
    UNION ALL
    SELECT d + 1 FROM divisors WHERE d < FLOOR(SQRT(1000))
),
find_prime AS (
    SELECT c.i, d.d, MOD(c.i, d.d) AS modulus,
        CASE
            WHEN c.i <= 1 THEN 1
            WHEN c.i <= 3 THEN 0
            WHEN MOD(c.i, d.d) = 0 THEN 1
            ELSE 0
        END AS is_not_prime
    FROM candidates c
    JOIN divisors d
    ON c.i > d.d
),
primes_only AS (
    SELECT i
    FROM find_prime
    GROUP BY i
    HAVING SUM(is_not_prime) = 0
)
SELECT CONCAT('2&3&', GROUP_CONCAT(i ORDER BY i SEPARATOR '&')) AS primes
FROM primes_only;

  • nandun5
     + 0 comments
    /*
Enter your query here.
Please append a semicolon ";" at the end of the query and enter your query in a single line to avoid error.
*/

DECLARE @l INT = 1000

DECLARE @n INT = 2

DECLARE @primes VARCHAR(MAX) = ''

WHILE @n <= @l
BEGIN
    
    DECLARE @d INT = 2
    DECLARE @b BIT = 1
    
    WHILE @d < @n
    BEGIN
        
        IF @n % @d = 0 AND @n <> @d
        BEGIN
            SET @b = 0
            BREAK;
        END
        
        SET @d = @d + 1
    END
    
    IF @b = 1 
    BEGIN
        SET @primes = @primes + '&' + CAST(@n as VARCHAR(MAX))
    END

    SET @n = @n + 1
END

SET @primes = SUBSTRING(@primes, 2, LEN(@primes) - 1)

print @primes

  • chaurasiaaryaj
     + 0 comments

    MYSQL

    WITH RECURSIVE numbers AS ( SELECT 2 AS num UNION ALL SELECT num + 1 FROM numbers WHERE num + 1 <= 1000 ), primes AS ( SELECT num FROM numbers n WHERE NOT EXISTS ( SELECT 1 FROM numbers d WHERE d.num < n.num AND d.num > 1 AND n.num % d.num = 0 ) ) SELECT GROUP_CONCAT(num ORDER BY num SEPARATOR '&') AS prime_list FROM primes;

  • SVVBathini
     + 0 comments

    For MySQL

    DELIMITER ^^

CREATE PROCEDURE prime_numbers()
BEGIN
        DECLARE n INT DEFAULT 3;
        DECLARE res VARCHAR(2000) DEFAULT "2";
        
        loop1: WHILE n <= 1000 DO
                SET @i = 2;
                SET @isPrime = 1;
                
                loop2: WHILE @i <= CEIL(n/2) DO
                        IF n % @i = 0 THEN
                            SET @isPrime  = 0;
                            LEAVE loop2;
                        END IF;
                        SET @i = @i+1;
                END WHILE loop2;
                
                IF @isPrime  = 1 THEN
                    SET res = CONCAT(res,"&",n);
                END IF;
                
                SET n = n+1;
        END WHILE loop1;
        
        SELECT res;
END ^^

DELIMITER ;

CALL prime_numbers();