I have tbl_parent like this in Oracle SQL, sample data is given below:
Id(primary key) parentid childid
1 1 2
2 1 3
3 2 1
4 3 1 -- This row is wrong
In above table, some rows are incorrectly inserted, for example, if parent_id 1 has child_id 3 then parent_id 3 should not have child_id 1 as 3 is already child of 1 so can not be parent, I have 5000+ rows and want to find these incorrect rows, any help please?
greatest and least functions might be used as
select least(parentid,childid) as least_par_chi_id,
greatest(parentid,childid) as greatest_par_chi_id
from tab
group by greatest(parentid,childid), least(parentid,childid)
having count(*)>1;
Basically you are looking for cycles in your table.
The Oracle functionality to indentify cycles in hierarchical query is
CONNECT BY NOCYCLE and CONNECT_BY_ISCYCLE
This query show all nodes that lead to cycle - column is_Cycle = 1
select tbl.* ,
CONNECT_BY_ISCYCLE is_Cycle,
SYS_CONNECT_BY_PATH(childid, '/') path
from tbl
CONNECT BY NOCYCLE PRIOR childid = parentid
For your data the result is
PARENTID CHILDID IS_CYCLE PATH
---------- ---------- ---------- ----------
1 2 0 /2
2 1 1 /2/1
1 3 1 /2/1/3
1 3 0 /3
3 1 1 /3/1
1 2 1 /3/1/2
2 1 0 /1
1 2 1 /1/2
1 3 1 /1/3
3 1 0 /1
1 2 1 /1/2
1 3 1 /1/3
Note taht each cycle is recognised on several places, so you get some redundant data.
The advantage of this apprach is, that it works for longer cycles too (where the simple GROUP BY approach fails).
Example for cycle of the length 3:
create table tbl as
select 1 parentid, 2 childid from dual union all
select 2 parentid, 3 childid from dual union all
select 3 parentid, 1 childid from dual;
PARENTID CHILDID IS_CYCLE PATH
---------- ---------- ---------- ----------
1 2 0 /2
2 3 0 /2/3
3 1 1 /2/3/1
2 3 0 /3
3 1 0 /3/1
1 2 1 /3/1/2
3 1 0 /1
1 2 0 /1/2
2 3 1 /1/2/3
Related
AID
BID
STATE
1
1
1
1
2
3
1
3
3
2
1
0
2
2
3
2
3
3
3
1
3
3
2
0
3
3
3
I am trying to find AID records which doesnt have any 0 state in this example AID = 1 (will be multiple records)
If you would like to find all the AID with no 0 state records you may use
SELECT
AID
FROM
mytable
GROUP BY
AID
HAVING
COUNT(
CASE WHEN STATE=0 THEN 1 END
)=0;
AID
1
or if you would like to find all AID records where the state is not 0 for any AID record you may use the following.
SELECT
*
FROM
mytable
WHERE AID NOT IN (
SELECT AID FROM mytable WHERE STATE=0
)
AID
BID
STATE
1
1
1
1
2
3
1
3
3
Let me know if this works for you.
Hi Experts I have a table like this
T1
Order_no
Qty
1
3
2
5
3
1
4
3
I need to generate a column 'serial no' having values based on 'qty'
Output needed
OrderNo
Qty
SerailNo
1
3
1
1
3
2
1
3
3
2
5
1
2
5
2
2
5
3
2
5
4
2
5
5
3
1
1
4
3
1
4
3
2
4
3
3
Any suggestions?
Thanks in advance!!
You don't mention the specific database so I'll assume you are using PostgreSQL, aren't you?
You can use a Recursive CTE to expand the rows. For example:
with recursive
n as (
select order_no, qty, 1 as serial_no from t1
union all
select order_no, qty, serial_no + 1
from n
where serial_no < qty
)
select * from n order by order_no, serial_no
Result:
order_no qty serial_no
--------- ---- ---------
1 3 1
1 3 2
1 3 3
2 5 1
2 5 2
2 5 3
2 5 4
2 5 5
3 1 1
4 3 1
4 3 2
4 3 3
See running example at DB Fiddle.
EDIT FOR ORACLE
If you are using Oracle the query changes a bit to:
with
n (order_no, qty, serial_no) as (
select order_no, qty, 1 from t1
union all
select order_no, qty, serial_no + 1
from n
where serial_no < qty
)
select * from n order by order_no, serial_no
Result:
ORDER_NO QTY SERIAL_NO
--------- ---- ---------
1 3 1
1 3 2
1 3 3
2 5 1
2 5 2
2 5 3
2 5 4
2 5 5
3 1 1
4 3 1
4 3 2
4 3 3
See running example at db<>fiddle.
You should first provide the database you're using. Whether it's oracle, Sql Server, PostGreSQL will determine which procedural language to use. It's very likely that you'll need to do this in two steps:
1st: Duplicate the number of rows based on the column Qty using a decreasing loop
2nd: You'll need to create a sequential partionned column based on the Qty column
I have 1 table, which refers by value to rows in the same table
Example table:
ID PARENT_ID NAME
1 0 john
2 1 jane
3 2 smigy
4 2 gujo
5 1 duby
6 1 ruby
7 5 foo
8 2 bar
9 3 baz
10 3 qux
The root-parent has parent 0 (just so it wouldn't be null), in this case there's
1 root-parent - parent(0)=1.
root-parent has 1lvl children - parent(1)=2;5;6.
1lvl children has 2lvl children - parent(2)=3;4;8. parent(5)=7. parent(6) has nothing.
2lvl children has 3lvl children - parent(3)=9;10. parent(4) has nothing. parent(8) has nothing.
There is no lvl4 children or anything with depth beyond 4.
And I need to create a script (presumably SQL query - need to avoid function/procedure/etc.) that would index rows based on their position under their parent.
Just like if I'd select all root-parent's and get (rownum-1)
The goal table should look like this:
ID PARENT_ID NAME ROW_INDEX
1 0 john 0
2 1 jane 0
3 2 smigy 0
4 2 gujo 1
5 1 duby 1
6 1 ruby 2
7 5 foo 0
8 2 bar 2
9 3 baz 0
10 3 qux 1
I'm planing to add this column and thus the query will be executed only once. I've played by selecting seperate depth rows, but then I don't really know how to count inside/between group by (even if that is possible).
P.S. A better/good column name suggestion would also be very appreciated.
User row_number()
select mt.*, row_number() over(partition by parent_id order by id) - 1 as rn
from MyTable mt
I have the follow table: example:
nodes:
id_node id_parent
--------------------
1 3
3 2
2 -1
I want to insert in other table the level of descent. For example:
ancestor:
id_node id_parent level
-------------------------
1 3 1
3 2 1
1 2 2
Should be something like this:
SELECT id_node, id_parent, level
FROM nodes
START WITH id_parent = -1
CONNECT BY PRIOR id_node = id_parent
The simple question is how can you take a set of records with a PK and create exactly two records for each source with a slightly altered key for the duplicate? In other words, I take 4000 records and produce 8000 records where 4000 are identical and the other 4000 have a slightly altered key. I cannot do a union because this is essentially two selects (long story).
The rest gets complicated, but maybe necessary to provide examples.
This is my original set (it contains over 4000 records)
dateGroup areaGroup itemID editionID
1 1 1 1
1 1 1 2
1 2 1 1
1 2 2 1
2 1 1 1
2 1 1 2
2 2 1 1
2 2 1 2
For each record I need to create a duplicate record ganging the areaGroups together under '0', then create a comma separated list of original areaGroups as a separate field. (The "why" is some dumb programmer (me) made a mistake about 15 years ago.) I can renumber the editionIDs as necessary, but the original and duplicate record must have the same editionID (thus why a union wouldn't work). The PK remains the same as above (all fields)
dateGroup areaGroup itemID editionID aGroups
1 0 1 1 1
1 0 1 2 1
1 0 1 1 2 // Duplicate (EditionID)
1 0 2 1 2
2 0 1 1 1
2 0 1 2 1
2 0 1 1 2 // Duplicate (EditionID)
2 0 1 2 2
The end result would renumber the editionID as needed to make the record unique.
dateGroup areaGroup itemID editionID aGroups (EditionID is what is altered)
1 0 1 1 1
1 0 1 2 1
1 0 1 2 2 1 changed to 2 (one more than row 1)
1 0 2 1 2
2 0 1 1 1
2 0 1 2 1
2 0 1 2 2 1 changed to 2 (one more than row 1)
2 0 1 2 2
1 1 1 1
1 1 1 2
1 2 1 2 1 changed to 2 (editionID) to match
1 2 2 1
2 1 1 1
2 1 1 2
2 2 1 2 1 changed to 2 to match above
2 2 1 2
I know you could calculate the editionID like a row rank like so:
select row_number() over (
partition by dateGroup, itemID
order by dateGroup, itemID) as editionID
So all I need is to know how to duplicate the records from a single set
do a cross join on a derived table:
( select 1 as aGroups union all select 2 )
I'd create a temporary table with duplicates and their count.
Then I'd filter the original table to have only unique rows, and insert another row for each row in the temporary table, incrementing their editionID.
In MySQL, I'd use user #variables; not sure about MS SQL.
Did you try UNION ALL instead of just UNION
UDPATE perhaps I misunderstood the problem and I thought you were having a problem with the union loosing the duplicates.
If the problem is that you want to do a row_number over a union why don't you do somthing like
select row_number() over (
partition by dateGroup, itemID
order by dateGroup, itemID) as editionID
FROM
(
SELECT
dateGroup, itemID
FROM TableA
UNION ALL
SELECT
dateGroup, itemID
FROM TableB
) Data