I have a requirement to add dynamic rows based on results fetched by SQL query. I've written a query that shows result something like the below:
| Value | Name |
|---|---|
| 1 | Test 1 |
| 2 | Test 2 |
| . | . |
| n | n |
The above SQL result will return a dynamic number of rows. (Number of rows not fixed)
So I want to add a column with values like Parent1, Parent2, and so on based on the number of rows. Suppose my query returns a total of 300 rows then the first row should be named as Parent1 in column Value and In name both, Then result of my query until the 150th row then another dynamic row with value column as Parent2 field and so on like below table.
| Value | Name |
|---|---|
| Parent1 | Parent 1 |
| 1 | Test 1 |
| 2 | Test 2 |
| . | . |
| Parent2 | Parent2 |
| 151 | Test 151 |
| . | . |
| n | n |
Please Note : I can not use DDL or DML Commands to achive this.
CodePudding user response：
Suppose this is your original query
select
to_char(rownum) value, 'Test '||rownum name
from dual
connect by level <= 6
;
VALUE NAME
---------- ----------
1 Test 1
2 Test 2
3 Test 3
4 Test 4
5 Test 5
6 Test 6
and you want to introdues two header Parent lines.
You may use NTILEto split the original query in two parts ordering on some column (here VALUE)
NTILE(2) OVER (ORDER BY VALUE) nt
Change the number in NTILE to increase the split.
The query below uses the original query as base, calculates the NTILE for the split, adds with UNION ALL the Parent rows.
Most importantly covers the correct order using the NTILE number (nt), the source (first parent row than data) and the value.
with dt as ( /* your original query */
select
to_char(rownum) value, 'Test '||rownum name
from dual
connect by level <= 6
)
select VALUE, NAME,
NTILE(2) OVER (ORDER BY VALUE) nt, /* modify to change split */
1 src
from dt
union all
select
'Parent'||rownum value,
'Parent'||rownum name,
rownum nt, 0 src
from dual connect by level <= 2 /* modify to change split */
order by nt, src, value;
VALUE NAME NT SRC
---------------------------------------------- ---------------------------------------------- ---------- ----------
Parent1 Parent1 1 0
1 Test 1 1 1
2 Test 2 1 1
3 Test 3 1 1
Parent2 Parent2 2 0
4 Test 4 2 1
5 Test 5 2 1
6 Test 6 2 1
CodePudding user response：
The query below will generate a list of parents/non-parents using CONNECT BY. You can change the 300 to the number of rows you want to generate and you change the 150 in the query to have a parent generated that many number of rows.
SELECT LEVEL,
CASE
WHEN MOD (LEVEL, 150) = 0 OR LEVEL = 1
THEN
'Parent' || TO_CHAR (TRUNC (LEVEL / 150) 1)
ELSE
TO_CHAR (LEVEL)
END AS VALUE,
CASE
WHEN MOD (LEVEL, 150) = 0 OR LEVEL = 1
THEN
'Parent' || TO_CHAR (TRUNC (LEVEL / 150) 1)
ELSE
'Test ' || TO_CHAR (LEVEL)
END AS VALUE
FROM DUAL
CONNECT BY LEVEL <= 300;
CodePudding user response：
A similar approach, more dynamic.
col value for 9999
col name for a20
define limit = &1
define split = &2
select level as lvl,
case
when mod (level, &&split) = 0 or level = 1
then
'parent' || to_char (trunc (level / &&split) 1)
else
to_char (level)
end as name,
case
when mod (level, &&split) = 0 or level = 1
then
'parent' || to_char (trunc (level / &&split) 1)
else
'test ' || to_char (level)
end as value
from dual
connect by level <= &&limit
/
Executed as script, you inform two parameters, the total number of values and the split value.
SQL> @generate.sql 100 50
old 3: when mod (level, &&split) = 0 or level = 1
new 3: when mod (level, 50) = 0 or level = 1
old 5: 'parent' || to_char (trunc (level / &&split) 1)
new 5: 'parent' || to_char (trunc (level / 50) 1)
old 10: when mod (level, &&split) = 0 or level = 1
new 10: when mod (level, 50) = 0 or level = 1
old 12: 'parent' || to_char (trunc (level / &&split) 1)
new 12: 'parent' || to_char (trunc (level / 50) 1)
old 17: connect by level <= &&limit
new 17: connect by level <= 100
LVL NAME VALUE
---------- -------------------- ----------------------------------------------
1 parent1 parent1
2 2 test 2
3 3 test 3
4 4 test 4
5 5 test 5
6 6 test 6
7 7 test 7
8 8 test 8
9 9 test 9
10 10 test 10
11 11 test 11
LVL NAME VALUE
---------- -------------------- ----------------------------------------------
12 12 test 12
13 13 test 13
14 14 test 14
15 15 test 15
16 16 test 16
17 17 test 17
18 18 test 18
19 19 test 19
20 20 test 20
21 21 test 21
22 22 test 22
LVL NAME VALUE
---------- -------------------- ----------------------------------------------
23 23 test 23
24 24 test 24
25 25 test 25
26 26 test 26
27 27 test 27
28 28 test 28
29 29 test 29
30 30 test 30
31 31 test 31
32 32 test 32
33 33 test 33
LVL NAME VALUE
---------- -------------------- ----------------------------------------------
34 34 test 34
35 35 test 35
36 36 test 36
37 37 test 37
38 38 test 38
39 39 test 39
40 40 test 40
41 41 test 41
42 42 test 42
43 43 test 43
44 44 test 44
LVL NAME VALUE
---------- -------------------- ----------------------------------------------
45 45 test 45
46 46 test 46
47 47 test 47
48 48 test 48
49 49 test 49
50 parent2 parent2
51 51 test 51
52 52 test 52
53 53 test 53
54 54 test 54
55 55 test 55
LVL NAME VALUE
---------- -------------------- ----------------------------------------------
56 56 test 56
57 57 test 57
58 58 test 58
59 59 test 59
60 60 test 60
61 61 test 61
62 62 test 62
63 63 test 63
64 64 test 64
65 65 test 65
66 66 test 66
LVL NAME VALUE
---------- -------------------- ----------------------------------------------
67 67 test 67
68 68 test 68
69 69 test 69
70 70 test 70
71 71 test 71
72 72 test 72
73 73 test 73
74 74 test 74
75 75 test 75
76 76 test 76
77 77 test 77
LVL NAME VALUE
---------- -------------------- ----------------------------------------------
78 78 test 78
79 79 test 79
80 80 test 80
81 81 test 81
82 82 test 82
83 83 test 83
84 84 test 84
85 85 test 85
86 86 test 86
87 87 test 87
88 88 test 88
LVL NAME VALUE
---------- -------------------- ----------------------------------------------
89 89 test 89
90 90 test 90
91 91 test 91
92 92 test 92
93 93 test 93
94 94 test 94
95 95 test 95
96 96 test 96
97 97 test 97
98 98 test 98
99 99 test 99
LVL NAME VALUE
---------- -------------------- ----------------------------------------------
100 parent3 parent3
100 rows selected.