task 55

Author: BEPb

README.md

@@ -78,6 +78,7 @@
 52. Проблемы - [Challenges](./tasks/52.md)
 53. Нарисуй треугольник 1 - [Draw The Triangle 1](./tasks/53.md)
 54. Нарисуй треугольник 2 - [Draw The Triangle 2](./tasks/54.md)
+55. Печать простых чисел - [Print Prime Numbers](./tasks/55.md)
 
 
 ## В процессе...  , будет дополнено)

tasks/55.md

@@ -3,20 +3,64 @@
 <img src="./art/55.png" alt="solution" >
 
 #### eng:
+Write a query to print all prime numbers less than or equal to . 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  would be:
 
 
 #### рус:
+Напишите запрос, чтобы вывести все простые числа, меньшие или равные . Выведите результат в одну строку и используйте символ амперсанда () в качестве разделителя (вместо пробела).
 
+Например, вывод для всех простых чисел будет таким:
 
 
 #### код с коментариями:
 ```sql
+SELECT 
+    CONCAT(2, '&', REPLACE(GROUP_CONCAT(T2.n ORDER BY T2.n), ',', '&')) 
+FROM 
+    ( SELECT 
+        T.n FROM ( WITH recursive counter AS ( 
+            SELECT  
+                2 AS n 
+                UNION SELECT 
+                    n + 1 
+                FROM counter 
+                WHERE n < 1000 ) 
+             SELECT 
+                c1.n AS n, 
+                MOD(c1.n, c2.n) AS r 
+                FROM counter AS c1, 
+        counter AS c2 
+        WHERE c1.n > c2.n ) AS T 
+        GROUP BY T.n 
+        HAVING MIN(T.r) > 0 
+        ORDER BY T.n ) AS T2;
 
 ```
 
 #### код для hackerrank:
 ```sql
+SELECT 
+    CONCAT(2, '&', REPLACE(GROUP_CONCAT(T2.n ORDER BY T2.n), ',', '&')) 
+FROM 
+    ( SELECT 
+        T.n FROM ( WITH recursive counter AS ( 
+            SELECT  
+                2 AS n 
+                UNION SELECT 
+                    n + 1 
+                FROM counter 
+                WHERE n < 1000 ) 
+             SELECT 
+                c1.n AS n, 
+                MOD(c1.n, c2.n) AS r 
+                FROM counter AS c1, 
+        counter AS c2 
+        WHERE c1.n > c2.n ) AS T 
+        GROUP BY T.n 
+        HAVING MIN(T.r) > 0 
+        ORDER BY T.n ) AS T2;
 
 ```
 

tasks/55.sql

@@ -0,0 +1,20 @@
+SELECT
+    CONCAT(2, '&', REPLACE(GROUP_CONCAT(T2.n ORDER BY T2.n), ',', '&'))
+FROM
+    ( SELECT
+        T.n FROM ( WITH recursive counter AS (
+            SELECT
+                2 AS n
+                UNION SELECT
+                    n + 1
+                FROM counter
+                WHERE n < 1000 )
+             SELECT
+                c1.n AS n,
+                MOD(c1.n, c2.n) AS r
+                FROM counter AS c1,
+        counter AS c2
+        WHERE c1.n > c2.n ) AS T
+        GROUP BY T.n
+        HAVING MIN(T.r) > 0
+        ORDER BY T.n ) AS T2;