SHOW CREATE FUNCTION { function_name | database_name.function_name }

SHOW CREATE FUNCTION is_prime\G

*** 1. row ***
            Function: is_prime
            sql_mode: STRICT_ALL_TABLES,NO_AUTO_CREATE_USER
     Create Function: CREATE OR REPLACE FUNCTION `is_prime`(n bigint(20) NOT NULL) RETURNS bigint(20) NULL DEFINER = 'root'@'%' AS
  BEGIN
    IF n <= 1 THEN
      RETURN FALSE;
    END IF;
    FOR i IN 2 .. (n-1) LOOP
      EXIT WHEN i * i > n;
      IF n % i != 0 THEN
        CONTINUE;
      END IF;
      RETURN FALSE;
    END LOOP;
    RETURN TRUE;
  END;
character_set_client: utf8
collation_connection: utf8mb4_general_ci
1 row in set (0.00 sec)