Oracle 18c

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create table tower_test
(Tower_Number        VARCHAR2(12),
 Tower_Side          VARCHAR2(1),
 Tower_Height        NUMBER,
 Tower_Height_Um     VARCHAR2(1) default 'm',
 Client              VARCHAR2(25),
 Client_Start_Height NUMBER,
 Range_From          NUMBER,
 Range_To            NUMBER);
-- No Client
INSERT ALL
-- Side A
-- Client 1 
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'A', 50, 'Client_1', 12, 17, 18)
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'A', 50, 'Client_1', 12, 22, 23)
-- Client 2
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'A', 50, 'Client_2', 24, 35, 36)
-- Client 3
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'A', 50, 'Client_3', 40, 40, 41)
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'A', 50, 'Client_3', 40, 47, 48)

-- Side B
-- Client 1
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'B', 50, 'Client_1', 12, 13, 14)
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'B', 50, 'Client_1', 12, 19, 20)
-- Client 2
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'B', 50, 'Client_2', 24, 31, 32)
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'B', 50, 'Client_2', 24, 37, 38)
-- Client 3
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'B', 50, 'Client_3', 40, 43, 44)
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'B', 50, 'Client_3', 40, 46, 47)

-- Side C
-- Client 1 
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'C', 50, 'Client_1', 12, 17, 18)
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'C', 50, 'Client_1', 12, 22, 23)
-- Client 2
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'C', 50, 'Client_2', 24, 28, 29)
-- Client 3
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'C', 50, 'Client_3', 40, 40, 41)
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'C', 50, 'Client_3', 40, 47, 48)

-- Side D
-- Client 1
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'D', 50, 'Client_1', 12, 19, 20)
-- Client 2
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'D', 50, 'Client_2', 24, 31, 32)
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'D', 50, 'Client_2', 24, 37, 38)
-- Client 3
 INTO tower_test (Tower_Number, Tower_Side, Tower_Height, Client, Client_Start_Height, Range_From, Range_To) VALUES ('123456_TWR1', 'D', 50, 'Client_3', 40, 46, 47)

SELECT 1 FROM DUAL;
20 rows affected

WITH CTE1_FLATTEND AS 
(
    SELECT 
      Tower_Number
    , Client
    , Client_Start_Height
    , Range_From
    , Range_To
    , COUNT(DISTINCT
            CASE
            WHEN Tower_Side IN ('A','C')
            THEN Tower_Side
            END) AS Total_AC
    , COUNT(DISTINCT
            CASE
            WHEN Tower_Side IN ('B','D')
            THEN Tower_Side
            END) AS Total_BD
    , COUNT(DISTINCT Tower_Side) AS Total_ABCD
    , MAX(Tower_Height) AS Tower_Height
    , MAX(Tower_Height_Um) AS Tower_Height_Um
    FROM tower_test
    GROUP BY
      Tower_Number
    , Client
    , Client_Start_Height
    , Range_From
    , Range_To
)
, CTE2_GAPS_ADDED AS
(
    SELECT
      Tower_Number
    , Client
    , Client_Start_Height
    , Client_Start_Height AS Next_Client_Start_Height
    , COALESCE(LAG(Range_To) 
        OVER (PARTITION BY Tower_Number, Client_Start_Height
              ORDER BY Range_From)+1, Client_Start_Height) AS Range_From
    , Range_From-1 AS Range_To
    , 'A' AS Avlblt_Type -- Available Gap
    , Tower_Height
    , Tower_Height_Um
    FROM CTE1_FLATTEND
   
    UNION

    SELECT
      Tower_Number
    , Client
    , Client_Start_Height
    , COALESCE(LEAD(Client_Start_Height) 
        OVER (PARTITION BY Tower_Number
              ORDER BY Range_From), Client_Start_Height) AS Next_Client_Start_Height
    , Range_To+1 AS Range_From
    , COALESCE(LEAD(Range_From) 
        OVER (PARTITION BY Tower_Number
              ORDER BY Range_From)-1, Tower_Height) AS Range_To
    , 'A' AS Avlblt_Type -- Available Gap
    , Tower_Height
    , Tower_Height_Um
    FROM CTE1_FLATTEND
   
    UNION ALL
    
    SELECT
      Tower_Number
    , Client
    , Client_Start_Height
    , Client_Start_Height AS Next_Client_Start_Height
    , Range_From
    , Range_To
    , CASE
      WHEN Total_ABCD = 1 THEN 'P' -- Partial
      WHEN Total_ABCD > 2 THEN 'F' -- Fault
      WHEN Total_AC = 2   THEN 'T' -- Taken A C
      WHEN Total_BD = 2   THEN 'T' -- Taken B D
      ELSE 'E' -- Exception
      END AS Avlblt_Type
    , Tower_Height
    , Tower_Height_Um
    FROM CTE1_FLATTEND
    
    UNION ALL
    
    SELECT
      Tower_Number
    , 'No Client' AS Client
    , 1 AS Client_Start_Height
    , 0 AS Next_Client_Start_Height
    , 0 AS Range_From
    , MIN(Client_Start_Height)-1 AS Range_To
    , 'T' AS Avlblt_Type
    , Tower_Height
    , Tower_Height_Um
    FROM CTE1_FLATTEND
    GROUP BY 
      Tower_Number
    , Tower_Height
    , Tower_Height_Um
) 
SELECT 
  Tower_Number
, Tower_Height
, Tower_Height_Um
, Client
, Avlblt_Type
, Range_From
, Range_To
--, Client_Start_Height
--, Next_Client_Start_Height
FROM CTE2_GAPS_ADDED
WHERE Range_From <= Range_To
  AND NOT (Client_Start_Height < Next_Client_Start_Height
           AND Range_From >= Next_Client_Start_Height)
ORDER BY Tower_Number, Range_From;


TOWER_NUMBER
TOWER_HEIGHT
TOWER_HEIGHT_UM
CLIENT
AVLBLT_TYPE
RANGE_FROM
RANGE_TO


123456_TWR1
50
m
No Client
T
0
11

123456_TWR1
50
m
Client_1
A
12
12

123456_TWR1
50
m
Client_1
P
13
14

123456_TWR1
50
m
Client_1
A
15
16

123456_TWR1
50
m
Client_1
T
17
18

123456_TWR1
50
m
Client_1
T
19
20

123456_TWR1
50
m
Client_1
A
21
21

123456_TWR1
50
m
Client_1
T
22
23

123456_TWR1
50
m
Client_2
A
24
27

123456_TWR1
50
m
Client_2
P
28
29

123456_TWR1
50
m
Client_2
A
30
30

123456_TWR1
50
m
Client_2
T
31
32

123456_TWR1
50
m
Client_2
A
33
34

123456_TWR1
50
m
Client_2
P
35
36

123456_TWR1
50
m
Client_2
T
37
38

123456_TWR1
50
m
Client_2
A
39
39

123456_TWR1
50
m
Client_3
T
40
41

123456_TWR1
50
m
Client_3
A
42
42

123456_TWR1
50
m
Client_3
P
43
44

123456_TWR1
50
m
Client_3
A
45
45

123456_TWR1
50
m
Client_3
T
46
47

123456_TWR1
50
m
Client_3
T
47
48

123456_TWR1
50
m
Client_3
A
49
50
TOWER_NUMBER	TOWER_HEIGHT	TOWER_HEIGHT_UM	CLIENT	AVLBLT_TYPE	RANGE_FROM	RANGE_TO
123456_TWR1	50	m	No Client	T	0	11
123456_TWR1	50	m	Client_1	A	12	12
123456_TWR1	50	m	Client_1	P	13	14
123456_TWR1	50	m	Client_1	A	15	16
123456_TWR1	50	m	Client_1	T	17	18
123456_TWR1	50	m	Client_1	T	19	20
123456_TWR1	50	m	Client_1	A	21	21
123456_TWR1	50	m	Client_1	T	22	23
123456_TWR1	50	m	Client_2	A	24	27
123456_TWR1	50	m	Client_2	P	28	29
123456_TWR1	50	m	Client_2	A	30	30
123456_TWR1	50	m	Client_2	T	31	32
123456_TWR1	50	m	Client_2	A	33	34
123456_TWR1	50	m	Client_2	P	35	36
123456_TWR1	50	m	Client_2	T	37	38
123456_TWR1	50	m	Client_2	A	39	39
123456_TWR1	50	m	Client_3	T	40	41
123456_TWR1	50	m	Client_3	A	42	42
123456_TWR1	50	m	Client_3	P	43	44
123456_TWR1	50	m	Client_3	A	45	45
123456_TWR1	50	m	Client_3	T	46	47
123456_TWR1	50	m	Client_3	T	47	48
123456_TWR1	50	m	Client_3	A	49	50