I need to do an incremental sum in Oracle.
My situation is the following:
RecordID Value
1 1
2 2
3 5
4 10
And I need to get something like this:
RecordID Sum_incremental
1 (1)
2 (1 + 2)
3 (1 + 2 + 5)
4 (1 + 2 + 5 + 10)
The clues: self join and group by.
The solution:
select a.recordid, sum(b.value) sum_incremental from mytable a, mytable b
where b.recordid <= a.recordid group by a.recordid
select recordid,
sum(value) over (order by recordid)
from some_data
Related
Consider, I have the following in a select query:
ID Flag
5 Y
5 Y
5 N
6 Y
6 Y
6 Y
6 N
I should be adding a new column count in the same select which counts the number of 'Y' records for the ID and assigns it to all. (Eg: ID=5 has 3 records. All of them should be assigned the count value as '2').
Output required in select query:
ID Flag count
5 Y 2
5 Y 2
5 N 2
6 Y 3
6 Y 3
6 Y 3
6 N 3
Use a window function:
select id,
flag,
count(case when flag = 'Y' then 1 end) over (partition by id) as "count"
from the_table
order by id;
The case expression will return null for flags with N and thus they will be ignored by the count() function
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0
I expect I'm just missing something, but if I run this query without the "connect by", I get 2 rows. When I add "connect by level <= 4", I would expect to get each of those 2 rows 4 times. The actual result is different.
Can anyone help me understand what's happening here? I'm not looking for a solution that only repeats each row 4 times - I've already got that. I'm just looking to understand what's happening and why.
with alpha as (
select 1 as id
from dual
),
beta as (
select 1 as alpha_id,
1 as beta_no
from dual
union all
select 1 as alpha_id,
2 as beta_no
from dual
)
select a.id,
b.beta_no,
level as the_level
from alpha a
inner join beta b
on b.alpha_id = a.id
connect by level <= 4
order by a.id,
b.beta_no,
level
;
ID BETA_NO THE_LEVEL
1 1 1
1 1 2
1 1 2
1 1 3
1 1 3
1 1 3
1 1 3
1 1 4
1 1 4
1 1 4
1 1 4
1 1 4
1 1 4
1 1 4
1 1 4
1 2 1
1 2 2
1 2 2
1 2 3
1 2 3
1 2 3
1 2 3
1 2 4
1 2 4
1 2 4
1 2 4
1 2 4
1 2 4
1 2 4
1 2 4
30 rows selected
Many thanks to mathguy. The second link he provided in the answer below had exactly what I was looking for. Specifically:
1 with t as (select 1 as id from dual union all
2 select 2 from dual)
3 --
4 select id, level
5 ,prior id
6 ,sys_connect_by_path(id,'=>') as cpath
7 from t
8* connect by level <= 3
SQL> /
ID LEVEL PRIORID CPATH
---------- ---------- ---------- --------------------------------------------------
1 1 =>1
1 2 1 =>1=>1
1 3 1 =>1=>1=>1
2 3 1 =>1=>1=>2
2 2 1 =>1=>2
1 3 2 =>1=>2=>1
2 3 2 =>1=>2=>2
2 1 =>2
1 2 2 =>2=>1
1 3 1 =>2=>1=>1
2 3 1 =>2=>1=>2
2 2 2 =>2=>2
1 3 2 =>2=>2=>1
2 3 2 =>2=>2=>2
14 rows selected.
It's clear to me from that example, but I'd be hard-pressed to succinctly put it into words.
With no condition other than "level <= 4", every row from the original table, view etc. (from the join, in this case) will produce two rows at level 2, then four more rows at level 3, and 8 more at level 4. "Connect by" is essentially a succession of joins, and you are doing cross joins if you have no condition with the PRIOR operator.
You probably want to add "and prior a.id = a.id". This will lead to Oracle complaining about cycles (because Oracle decides a cycle is reached when it sees the same values in the columns subject to PRIOR). That, in turn, is solved by adding a third condition, usually "and prior sys_guid() is not null".
(Edited; the original answer made reference to NOCYCLE, which is not needed when using the "prior sys_guid() is not null" approach.)
This has been discussed recently on OTN: https://community.oracle.com/thread/3999985
Same question discussed here: https://community.oracle.com/thread/2526535
To illustrate Mathguy's answer, you are missing some predicates out of your CONNECT BY clause:
with alpha as (
select 1 as id
from dual
),
beta as (
select 1 as alpha_id,
1 as beta_no
from dual
union all
select 1 as alpha_id,
2 as beta_no
from dual
)
select a.id,
b.beta_no,
level as the_level
from alpha a
inner join beta b
on b.alpha_id = a.id
connect by level <= 4
AND PRIOR a.id = a.id
AND PRIOR b.beta_no = b.beta_no
AND PRIOR sys_guid() IS NOT NULL
order by a.id,
b.beta_no,
LEVEL;
ID BETA_NO THE_LEVEL
---------- ---------- ----------
1 1 1
1 1 2
1 1 3
1 1 4
1 2 1
1 2 2
1 2 3
1 2 4
An alternative would be to use the recursive with clause:
with alpha as (
select 1 as id
from dual
),
beta as (
select 1 as alpha_id,
1 as beta_no
from dual
union all
select 1 as alpha_id,
2 as beta_no
from dual
),
multiply (id, beta_no, rn) AS (SELECT a.id,
b.beta_no,
1 rn
FROM alpha a
INNER JOIN beta b
ON a.id = b.alpha_id
UNION ALL
SELECT ID,
beta_no,
rn + 1
FROM multiply
WHERE rn + 1 <= 4)
SELECT ID,
beta_no,
rn AS the_level
FROM multiply
order by id,
beta_no,
rn;
ID BETA_NO THE_LEVEL
---------- ---------- ----------
1 1 1
1 1 2
1 1 3
1 1 4
1 2 1
1 2 2
1 2 3
1 2 4
I have a table in Oracle that has a column that I would like to assign a value to from a set of possible values. I like to assign the values in order of the set, repeatedly, for the entire table.
For example:
If the set of values is {1, 2, 3}. I'd like to assign the values in this pattern until the last row is reached:
rowNum someCol valueCol
1 this 1
2 is 2
3 some 3
4 other 1
5 column 2
6 in 3
7 the 1
8 table 2
I can't figure out how to do this with a traditional update statement. Anone that could help with this problem?
Use Modulo to achieve desire result
UPDATE TableName
SET valueCol= CASE WHEN rowNum % 3 == 1 then 1
WHEN rowNum % 3 == 2 then 2
WHEN rowNum % 3 == 0 then 3
END
update tablename
set valuecol = case mod(rownum, 3) when 0 then 3 else mod(rownum, 3) end
;
Hi what i need to do is create a select statement which outputs the sum of the first character in a field within the table so the output would look something like
A,12
B,0
C,20
D,14
E,0
ect...
The table is called contacts, in the above there was 12 occurrences of people whose names begin with the letter A
I hope i have explained this correctly
Let's understand this with EMP table example.
SQL> with
2 letters
3 as
4 (select chr( ascii('A')+level-1 ) letter
5 from dual
6 connect by level <= 26
7 )
8 SELECT substr(ename, 1, 1) AS init_name,
9 count(*) cnt
10 FROM emp
11 WHERE substr(ename, 1, 1) IN (SELECT letter from letters)
12 GROUP BY substr(ename, 1, 1)
13 UNION
14 SELECT l.letter AS init_name,
15 0 cnt
16 FROM letters l
17 WHERE l.letter NOT IN (SELECT substr(ename, 1, 1) FROM emp)
18 ORDER BY init_name
19 /
I CNT
- ----------
A 2
B 1
C 1
D 0
E 0
F 1
G 0
H 0
I 0
J 2
K 1
L 0
M 2
N 0
O 0
P 0
Q 0
R 0
S 2
T 1
U 0
V 0
W 1
X 0
Y 0
Z 0
26 rows selected.
SQL>
So, it gives the count of each letter of first name, and for the other letters which does not exist in the first name, the count is 0.
Generate the 26 letters using connect then left join to the first letter of the name and count them:
select letter, count(name) count
from (select chr(ascii('A')+level-1) letter from dual connect by level < 27) l
left join emp on substr(name, 1, 1) = letter
group by letter order by 1
See SQLFiddle
Attribution: My technique of generating letters uses elements of Lalit's answer.
I have a table which has a column call numbers
Numbers
------
3
5
I am trying to get the factorial of those. I am using the below logic but not with proper result
Select
Numbers
,EXP(SUM(LN(Numbers)) OVER (ORDER BY Numbers)) Factorial
FROM testTbl
*Output
*
Numbers Factorial
------ ---------
3 3.00000000000000000000000000000000000001
5 15.0000000000000000000000000000000000002
What is wrong? Please help
Expected
--------
Numbers Factorial
------ ---------
3 6
5 120
Thanks in advance
I've had a go at this from another angle, trying to do it all in a SQL statement (using your table testTbl and the column numbers).
This is what I've come up with, see if it suits you:
SELECT testtbl.numbers,
ROUND( EXP( SUM( LN( t1.n ) ) ) ) AS factorial
FROM ( SELECT UNIQUE LEVEL n
FROM testtbl
CONNECT BY LEVEL <= numbers) t1,
( SELECT UNIQUE LEVEL n
FROM testtbl
CONNECT BY LEVEL <= numbers) t2,
testTbl
WHERE t1.n <= t2.n
AND t2.n = testTbl.numbers
GROUP BY testtbl.numbers
ORDER BY testtbl.numbers;
Gives the output:
Numbers Factorial
3 6
5 120
Hope it helps...
Were it me, I'd create a factorial function and call that user-defined function in my query. Something like
SQL> create function factorial( p_n in number )
2 return number
3 is
4 begin
5 if( p_n = 1 )
6 then
7 return p_n;
8 else
9 return p_n * factorial( p_n - 1 );
10 end if;
11 end;
12 /
Function created.
SQL> with t as (
2 select 3 num from dual
3 union all
4 select 5 from dual
5 )
6 select num,
7 factorial(num)
8 from t;
NUM FACTORIAL(NUM)
---------- --------------
3 6
5 120
If for some reason you cannot define a new function and you really want to do it in SQL, you'll can generate all the numbers less than the number in your table and then aggregate those generated numbers.
SQL> ed
Wrote file afiedt.buf
1 with t as (
2 select 3 num from dual
3 union all
4 select 5 from dual
5 )
6 select t.num,
7 exp( sum(ln(gen.num))) factorial
8 from (select level num
9 from dual
10 connect by level <= (select max(t.num) from t)) gen,
11 t
12 where gen.num <= t.num
13* group by t.num
SQL> /
NUM FACTORIAL
---------- ----------
5 120
3 6