Akina

WITH cte AS (
  SELECT id, 
         num, 
         LAG(num) OVER (ORDER BY id) lag_num
  FROM test
)
SELECT id, 
       num,
       CASE WHEN num <> 0
            THEN SUM(CASE WHEN num <> 0 AND lag_num = 0 THEN 1 ELSE 0 END) OVER (ORDER BY id) 
            ELSE 0
            END [group]
FROM cte

Select * 
from Employees
where [Employee ID] != ALL ( SELECT 90 UNION SELECT NULL );

SELECT *, AVG(RT) OVER (PARTITION BY Curr, YEAR(Dates) ORDER BY Dates) AS example
FROM src_table

WITH cte AS ( SELECT name, last_name, cnt FROM table
              UNION ALL
              SELECT name, last_name, cnt - 1 FROM cte WHERE cnt > 1 )
SELECT name, last_name FROM cte;

WITH 
cte1 AS ( SELECT id, col1 val FROM test UNION ALL 
          SELECT id, col2 FROM test UNION ALL
          SELECT id, col3 FROM test ),
cte2 AS ( SELECT id, GROUP_CONCAT(val ORDER BY val) FIO
          FROM cte1 
          GROUP BY id )

SELECT test.id, test.col1, test.col2, test.col3, GROUP_CONCAT(cte2_2.id) ids
FROM test
JOIN cte2 cte2_1 USING (id)
JOIN cte2 cte2_2 USING (FIO)
GROUP BY test.id, test.col1, test.col2, test.col3

id	col1		col2		col3		ids
1	Иванов		Иван		Иванович	1,2
2	Иван		Иванович	Иванов		1,2
3	Петров		Сергей		Алексеевич	3,4,5
4	Петров		Сергей		Алексеевич	3,4,5
5	Сергей		Алексеевич	Петров		3,4,5

выполняться будет на MS SQL Server, версию не могу сказать.

SELECT TOP 500 * 
FROM [table] 
WHERE  NOT EXISTS ( SELECT NULL 
                    FROM [Entities] 
                    WHERE [column] = '2' 
                      AND [table1].[Id] = [ClientTableId] )