First 1000 Prime Numbers with SQL Server

Question

I got program for Prime which gives only 2 as output. It should give me all based on java program I wrote.

Here is SQL I have created for Prime numbers. It is in SQL Ser

Answer 1

I had a similar solution to Larnu's, but went into a meeting and didn't want it to go to waste. It produces 1229 prime numbers (all the prime numbers lower than 10,000), in 7 seconds.

WITH 
E(n) AS(
    SELECT n FROM (VALUES(0),(0),(0),(0),(0),(0),(0),(0),(0),(0))E(n)
),
E2(n) AS(
    SELECT a.n FROM E a, E b
),
E4(n) AS(
    SELECT a.n FROM E2 a, E2 b
),
cteTally(n) AS(
    SELECT ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) n
    FROM E4
)
SELECT n
FROM cteTally t
WHERE (SELECT COUNT(*)
                FROM cteTally i
                WHERE t.n % i.n = 0
                AND i.n < t.n) = 1;

It can run a lot faster if we're allowed to use some hard-coded values.

WITH 
E(n) AS(
    SELECT n FROM (VALUES(0),(0),(0),(0),(0),(0),(0),(0),(0),(0))E(n)
),
E2(n) AS(
    SELECT a.n FROM E a, E b
),
E4(n) AS(
    SELECT a.n FROM E2 a, E2 b
),
cteTally(n) AS(
    SELECT ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) n
    FROM E4
)
SELECT *
FROM (VALUES(2),(3),(5),(7))x(n)
UNION ALL
SELECT n
FROM cteTally t
WHERE t.n % 2 <> 0
AND t.n % 3 <> 0 
AND t.n % 5 <> 0 
AND t.n % 7 <> 0 
AND (SELECT COUNT(*)
                FROM cteTally i
                WHERE t.n % i.n = 0
                AND i.n < t.n) = 1;

EDIT: The last version takes 1 second to find all the prime numbers below 10K, but goes up to 2.5 minutes to get all the prime numbers below 100K (9592 prime numbers).

EDIT 2: Here's an option that combines both versions to improve performance on large data sets. It won't need a large tally table either.

DECLARE @j INT = 1;

CREATE TABLE #Primes( N int);
BEGIN TRY
    BEGIN TRANSACTION;

    WHILE @j <= 1000000
    BEGIN
        INSERT INTO #Primes
        SELECT @J
        FROM #Primes
        WHERE @j % n = 0
        HAVING COUNT(*) <= 1;

        SET @j += 1;
    END;

    COMMIT TRANSACTION;

    SELECT * 
    FROM #Primes
    WHERE N <> 1;
END TRY
BEGIN CATCH
    ROLLBACK TRANSACTION;
    THROW;
END CATCH;

DROP TABLE #Primes;
GO