Константин Цветков

SELECT main_id AS [Код], 0 AS [Код.Код], 0 AS [Код.Код.Код], name_site AS [Текст]
  FROM MainTabMatrix
  WHERE name_site = 'Начальник РЭС'
UNION
SELECT MainTabMatrix.main_id, id_taks, 0, NameTask AS [Текст]
  FROM MainTabMatrix
    JOIN TasksM ON MainTabMatrix.main_id = TasksM.main_id
  WHERE name_site = 'Начальник РЭС'
UNION
SELECT MainTabMatrix.main_id, TasksM.id_taks, duties_id, NameDuties AS [Текст]
  FROM MainTabMatrix
    JOIN TasksM ON MainTabMatrix.main_id = TasksM.main_id
    JOIN Duties ON TasksM.id_task = Duties.id_task
  WHERE name_site = 'Начальник РЭС'
ORDER BY 1, 2, 3

SELECT user_id 
  FROM table_name 
  WHERE GROUP_CONCAT(profile_val) LIKE '%some%'
  GROUP BY user_id

SELECT * FROM games JOIN lvl ON … WHERE lvl=1
UNION
SELECT * FROM games JOIN lvl_hard ON … WHERE lvl=2

(Tag NVARCHAR(60), [StartTime] datetime, [EndTime] datetime)

CREATE PROCEDURE DowntimeCalculatePeriod
AS
  DECLARE @P TABLE ( ID INT IDENTITY, 
                     [Tag] NVARCHAR(60), [StartTime] DATETIME, [EndTime] DATETIME)
  DECLARE @DG1 NVARCHAR(60), @DT1 DATETIME
  DECLARE @DG0 NVARCHAR(60) = CHAR(0x19), @DT0 DATETIME = '2020'
  DECLARE @ID INT = -1
  DECLARE DowntimeCalc CURSOR FOR
    SELECT Tag, [DateTime] FROM Downtime ORDER BY 1, 2
  OPEN DowntimeCalc
  FETCH NEXT FROM DowntimeCalc INTO @DG1, @DT1
  WHILE @@FETCH_STATUS = 0 BEGIN
    IF ( @DG1 <> @DG0 ) OR (( @DG1 = @DG0 ) AND ( DATEDIFF( ss, @DT0, @DT1) > 90 )) BEGIN
      INSERT INTO @P ([Tag], [StartTime]) VALUES ( @DG1, @DT1 )
      SET @ID = SCOPE_IDENTITY()
    END ELSE BEGIN
      UPDATE @P SET [EndTime] = @DT1 WHERE ID = @ID
    END
    SET @DG0 = @DG1; SET @DT0 = @DT1
    FETCH NEXT FROM DowntimeCalc INTO @DG1, @DT1
  END
  CLOSE DowntimeCalc
  DEALLOCATE DowntimeCalc
  SELECT [Tag], [StartTime], [EndTime] FROM @P 
    WHERE NOT [EndTime] IS NULL 
    ORDER BY 1, 2
GO
--
EXECUTE DowntimeCalculatePeriod

SELECT order_id
  FROM order_statuses o
  WHERE (status = 'new')
    AND time = ( SELECT MAX(time) 
                     FROM order_statuses m 
                     WHERE (m.order_id = o.order_id))

SELECT * FROM table 
  WHERE CONCAT(' ', list, ' ') NOT LIKE '% 111 %'
  ORDER BY id LIMIT 1

SQL JOIN

CREATE TABLE appartament ( id int, name varchar(20), slots int );
INSERT appartament VALUES ( 1, 'Redison', 3 ), ( 2, 'Qubus Hotel', 2 ), ( 3, 'Hotel Nuber One', 4 );
CREATE TABLE reservation ( appartament_id int, guests int );
INSERT reservation VALUES ( 1, 2 ), ( 1, 1 ), ( 3, 1 );

SELECT name, slots, IFNULL( SUM( guests ), 0 ) AS CountGuest  
  FROM reservation
    RIGHT JOIN appartament ON id = appartament_id
  GROUP BY name
  HAVING CountGuest < slots

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