I'm trying to acheive through T-SQL (in a stored procedure) a way to copy a value from a parent into the child when retrieving rows. Here is some example data:
DROP TABLE TEST_LEVELS
CREATE TABLE TEST_LEVELS(
ID INT NOT NULL
,VALUE INT NULL
,PARENT_ID INT NULL
,LEVEL_NO INT NOT NULL
)
INSERT INTO TEST_LEVELS (ID, VALUE, PARENT_ID, LEVEL_NO) VALUES (1, 10000, NULL, 1)
INSERT INTO TEST_LEVELS (ID, VALUE, PARENT_ID, LEVEL_NO) VALUES (2, NULL, 1, 2)
INSERT INTO TEST_LEVELS (ID, VALUE, PARENT_ID, LEVEL_NO) VALUES (3, NULL, 2, 3)
INSERT INTO TEST_LEVELS (ID, VALUE, PARENT_ID, LEVEL_NO) VALUES (4, 20000, NULL, 1)
INSERT INTO TEST_LEVELS (ID, VALUE, PARENT_ID, LEVEL_NO) VALUES (5, NULL, 4, 2)
INSERT INTO TEST_LEVELS (ID, VALUE, PARENT_ID, LEVEL_NO) VALUES (6, 25000, 5, 3)
INSERT INTO TEST_LEVELS (ID, VALUE, PARENT_ID, LEVEL_NO) VALUES (7, NULL, 6, 4)
Selecting the data as follows:
SELECT ID, VALUE, LEVEL_NO
FROM TEST_LEVELS
results in:
+----+-------+----------+
| ID | VALUE | LEVEL_NO |
+----+-------+----------+
| 1 | 10000 | 1 |
| 2 | NULL | 2 |
| 3 | NULL | 3 |
| 4 | 20000 | 1 |
| 5 | NULL | 2 |
| 6 | 25000 | 3 |
| 7 | NULL | 4 |
+----+-------+----------+
But I need something like this (values are inherited by the parent):
+----+-------+----------+
| ID | VALUE | LEVEL_NO |
+----+-------+----------+
| 1 | 10000 | 1 |
| 2 | 10000 | 2 |
| 3 | 10000 | 3 |
| 4 | 20000 | 1 |
| 5 | 20000 | 2 |
| 6 | 25000 | 3 |
| 7 | 25000 | 4 |
+----+-------+----------+
Can this be achieved without using cursors (it must also run on SQL Server 2005)?
Use:
;with cte
as
(
select t.ID, t.VALUE, t.PARENT_ID, t.LEVEL_NO
from #t t
where t.Value is not null
union all
select t.ID, c.Value, t.PARENT_ID, t.LEVEL_NO
from cte c
join #t t on t.PARENT_ID = c.ID
where t.Value is null
)
select c.ID, c.Value, c.LEVEL_NO
from cte c
order by c.ID
Output:
ID Value LEVEL_NO
----------- ----------- -----------
1 10000 1
2 10000 2
3 10000 3
4 20000 1
5 20000 2
6 25000 3
7 25000 4
Maybe something like this:
;WITH cte_name(ID,VALUE,PARENT_ID,LEVEL_NO)
AS
(
SELECT
tbl.ID,
tbl.VALUE,
tbl.PARENT_ID,
tbl.LEVEL_NO
FROM
TEST_LEVELS AS tbl
WHERE
tbl.PARENT_ID IS NULL
UNION ALL
SELECT
tbl.ID,
ISNULL(tbl.VALUE,cte_name.VALUE),
tbl.PARENT_ID,
tbl.LEVEL_NO
FROM
cte_name
JOIN TEST_LEVELS AS tbl
ON cte_name.ID=tbl.PARENT_ID
)
SELECT
*
FROM
cte_name
ORDER BY
ID
One way to do it:
SELECT T.ID,
case when T.VALUE IS NULL
THEN (SELECT A.VALUE FROM TEST_LEVELS A WHERE A.ID = T.PARENT_ID)
ELSE T.VALUE
END,
T.LEVEL_NO
FROM TEST_LEVELS T
Related
Let's say I have a select which returns the following Data:
select nr, name, val_1, val_2, val_3
from table
Nr. | Name | Value 1 | Value 2 | Value 3
-----+------------+---------+---------+---------
1 | Max | 123 | NULL | NULL
1 | Max | NULL | 456 | NULL
1 | Max | NULL | NULL | 789
9 | Lisa | 1 | NULL | NULL
9 | Lisa | 3 | NULL | NULL
9 | Lisa | NULL | NULL | Hello
9 | Lisa | 9 | NULL | NULL
I'd like to condense the rows down to the bare minimum with.
I want the following result:
Nr. | Name | Value 1 | Value 2 | Value 3
-----+------------+---------+---------+---------
1 | Max | 123 | 456 | 789
9 | Lisa | 1 | NULL | Hello
9 | Lisa | 3 | NULL | NULL
9 | Lisa | 9 | NULL | NULL
For condensing the rows with Max (Nr. 1) a group by of the max values would help.
select nr, name, max(val_1), max(val_2), max(val_3)
from table
group by nr, name
But I am unsure how to get the desired results for Lisa (Nr. 9). The row for Lisa contains a value in the Value 3 column, in this example it's condensed with the first row that matches Nr and Name and has a Null value in Value 3.
I'm thankful for every input!
Basic principle is same as Vladimir's solution. This uses UNPIVOT and PIVOT
with cte as
(
select nr, name, col, val,
rn = row_number() over(partition by nr, name, col order by val)
from [table]
unpivot
(
val
for col in (val_1, val_2, val_3)
) u
)
select *
from (
select nr, name, rn, col, val
from cte
) d
pivot
(
max (val)
for col in ([val_1], [val_2], [val_3])
) p
Here is one way to do it. Assign a unique row number for each column by sorting them in such a way that NULLs come last and then join them back together using these row numbers and remove rows with all NULLs.
Run just the CTE first and examine the intermediate result to understand how it works.
Sample data
DECLARE #T TABLE (Nr varchar(10), Name varchar(10), V1 varchar(10), V2 varchar(10), V3 varchar(10));
INSERT INTO #T VALUES
('1', 'Max ', '123' , NULL , NULL ),
('1', 'Max ', NULL , '456', NULL ),
('1', 'Max ', NULL , NULL , '789'),
('9', 'Lisa', '1' , NULL , NULL ),
('9', 'Lisa', '3' , NULL , NULL ),
('9', 'Lisa', NULL , NULL , 'Hello'),
('9', 'Lisa', '9' , NULL , NULL );
Query
WITH CTE
AS
(
SELECT
Nr
,Name
,V1
,V2
,V3
-- here we use CASE WHEN V1 IS NULL THEN 1 ELSE 0 END to put NULLs last
,ROW_NUMBER() OVER (PARTITION BY Nr ORDER BY CASE WHEN V1 IS NULL THEN 1 ELSE 0 END, V1) AS rn1
,ROW_NUMBER() OVER (PARTITION BY Nr ORDER BY CASE WHEN V2 IS NULL THEN 1 ELSE 0 END, V2) AS rn2
,ROW_NUMBER() OVER (PARTITION BY Nr ORDER BY CASE WHEN V3 IS NULL THEN 1 ELSE 0 END, V3) AS rn3
FROM #T AS T
)
SELECT
T1.Nr
,T1.Name
,T1.V1
,T2.V2
,T3.V3
FROM
CTE AS T1
INNER JOIN CTE AS T2 ON T2.Nr = T1.Nr AND T2.rn2 = T1.rn1
INNER JOIN CTE AS T3 ON T3.Nr = T1.Nr AND T3.rn3 = T1.rn1
WHERE
T1.V1 IS NOT NULL
OR T2.V2 IS NOT NULL
OR T3.V3 IS NOT NULL
ORDER BY
T1.Nr, T1.rn1
;
Result
+----+------+-----+------+-------+
| Nr | Name | V1 | V2 | V3 |
+----+------+-----+------+-------+
| 1 | Max | 123 | 456 | 789 |
| 9 | Lisa | 1 | NULL | Hello |
| 9 | Lisa | 3 | NULL | NULL |
| 9 | Lisa | 9 | NULL | NULL |
+----+------+-----+------+-------+
I have a table below:
id | echantillon_dta | Est_en_double
1 | Bonjour | null
2 | Bonjour | null
3 | Bonjour | null
4 | Joke | null
5 | Joke | null
6 | | null
And after process query will show below:
id | echantillon_dta | Est_en_double
1 | Bonjour | 1
2 | Bonjour | 1
3 | Bonjour | 1
4 | Joke | 4
5 | Joke | 4
6 | | null
How to compare string vesus string? And how to update column like so?
you can use update by min(id) when Record_Details is same.
and there is a misdescription :
6 | Nope | 6 //No duplicates found, stay null
id 6 is no duplicate but isDuplicate column value is 6,shouldn't it be null?
so i use having count(1) > 1 to slove it.
CREATE TABLE Table1
("id" int, "Record_Details" varchar2(11), "isDuplicate" varchar2(4))
;
INSERT ALL
INTO Table1 ("id", "Record_Details", "isDuplicate")
VALUES (1, 'Hello World', NULL)
INTO Table1 ("id", "Record_Details", "isDuplicate")
VALUES (2, 'Hello World', NULL)
INTO Table1 ("id", "Record_Details", "isDuplicate")
VALUES (3, 'Hello World', NULL)
INTO Table1 ("id", "Record_Details", "isDuplicate")
VALUES (4, 'Joke', NULL)
INTO Table1 ("id", "Record_Details", "isDuplicate")
VALUES (5, 'Joke', NULL)
INTO Table1 ("id", "Record_Details", "isDuplicate")
VALUES (6, 'Nope', NULL)
SELECT * FROM dual
;
update (
select T.*
, (select min("id")
from Table1 Tmp
where Tmp."Record_Details" = T."Record_Details"
group by Tmp."Record_Details" having count(1) > 1 --No duplicates found, stay null
) as "new_isDuplicate"
from Table1 T
)
set "isDuplicate" = "new_isDuplicate"
6 rows affected
select * from Table1
id | Record_Details | isDuplicate
-: | :------------- | :----------
1 | Hello World | 1
2 | Hello World | 1
3 | Hello World | 1
4 | Joke | 4
5 | Joke | 4
6 | Nope | null
db<>fiddle here
You seem to want the minimum id with the same record_details.
This should work:
select t.*,
min(id) over (partition by record_details) as isDuplicate
from t;
If you want this as an update, a correlated subquery is a simple approach:
update t
set isduplicate = (select min(t2.id)
from t t2
where t2.record_details = t.record_details
);
You can use a MERGE statement and analytic function to find the duplicates:
Oracle Setup:
CREATE TABLE Table_name ( id, Record_Details, isDuplicate ) AS
SELECT 1, 'Hello World', CAST( NULL AS NUMBER ) FROM DUAL UNION ALL
SELECT 2, 'Hello World', NULL FROM DUAL UNION ALL
SELECT 3, 'Hello World', NULL FROM DUAL UNION ALL
SELECT 4, 'Joke', NULL FROM DUAL UNION ALL
SELECT 5, 'Joke', NULL FROM DUAL UNION ALL
SELECT 6, 'Nope', NULL FROM DUAL;
Merge:
MERGE INTO table_name dst
USING (
SELECT ROWID rid,
MIN( id ) OVER ( PARTITION BY Record_details ) AS dupe_id
FROM table_name
) src
ON (
dst.ROWID = src.RID
AND dst.id <> src.dupe_id -- remove this line if you want to update all rows
)
WHEN MATCHED THEN
UPDATE SET isDuplicate = dupe_id;
Output:
ID | RECORD_DETAILS | ISDUPLICATE
-: | :------------- | ----------:
1 | Hello World | null
2 | Hello World | 1
3 | Hello World | 1
4 | Joke | null
5 | Joke | 4
6 | Nope | null
db<>fiddle here
I have table
| Id | val |
| --- | ---- |
| 1 | null |
| 1 | qwe1 |
| 1 | qwe2 |
| 2 | null |
| 2 | qwe4 |
| 3 | qwe5 |
| 4 | qew6 |
| 4 | qwe7 |
| 5 | null |
| 5 | null |
is there any easy way to select distinct 'id' values with first non null 'val' values. if not exist then null. for example
result should be
| Id | val |
| --- | ---- |
| 1 | qwe1 |
| 2 | qwe4 |
| 3 | qwe5 |
| 4 | qew6 |
| 5 | null |
In your case a simple GROUP BY should be the solution:
SELECT Id
,MIN(val)
FROM dbo.mytable
GROUP BY Id
Whenever using a GROUP BY, you have to use an aggregate function on all columns, which are not listed in the GROUP BY.
If an Id has a value (val) other than NULL, this value will be returned.
If there are just NULLs for the Id, NULL will be returned.
As far as i unterstood (regarding your comment), this is exactly what you're going to approach.
If you always want to have "the first" value <> NULL, you'll need another sort criteria (like a timestamp column) and might be able to solve it with a WINDOW-function.
If you want the first non-NULL value (where "first" is based on id), then MIN() doesn't quite do it. Window functions do:
select t.*
from (select t.*,
row_number() over (partition by id
order by (case when val is not null then 1 else 2 end),
id
) as seqnum
from t
) t
where seqnum = 1;
SQL Fiddle:
Create Table from SQL Fiddle:
CREATE TABLE tab1(pid integer, id integer, val varchar(25))
Insert dummy records :
insert into tab1
values (1, 1 , null),
(2, 1 , 'qwe1' ),
(3, 1 , 'qwe2'),
(4, 2 , null ),
(5, 2 , 'qwe4' ),
(6, 3 , 'qwe5' ),
(7, 4 , 'qew6' ),
(8, 4 , 'qwe7' ),
(9, 5 , null ),
(10, 5 , null );
fire below query:
SELECT Id ,MIN(val) as val FROM tab1 GROUP BY Id;
I have a table:
+----+---------+-----------+--------------+-----------+
| id | item_id | attr_name | string_value | int_value |
+----+---------+-----------+--------------+-----------+
| 1 | 1 | 1 | prop_str_1 | NULL |
| 2 | 1 | 2 | prop_str_2 | NULL |
| 3 | 1 | 3 | NULL | 2 |
| 4 | 2 | 1 | prop_str_1 | NULL |
| 5 | 2 | 2 | prop_str_3 | NULL |
| 6 | 2 | 3 | NULL | 2 |
| 7 | 3 | 1 | prop_str_4 | NULL |
| 8 | 3 | 2 | prop_str_2 | NULL |
| 9 | 3 | 3 | NULL | 1 |
+----+---------+-----------+--------------+-----------+
And I want to select item_id with specific values for the attributes. But this is complicated by the fact that the fetching needs to do on several attributes. I've got to do it just using exists:
select *
from item_attribute as attr
where (name = 1 and string_value = 'prop_str_1')
and exists
(select item_id
from item_attribute
where item_id = attr.item_id and name = 2 and string_value = 'prop_str_2')
But the number of attributes can be increased, and therefore nested queries with exists will increase.
How can I rewrite this query to reduce the nested queries?
UPD:
create table item_attribute(
id int not null,
item_id int not null,
attr_name int not null,
string_value varchar(50),
int_value int,
primary key (id)
);
insert into item_attribute values (1, 1, 1, 'prop_str_1', NULL);
insert into item_attribute values (2, 1, 2, 'prop_str_2', NULL);
insert into item_attribute values (3, 1, 3, NULL, 2);
insert into item_attribute values (4, 2, 1, 'prop_str_1', NULL);
insert into item_attribute values (5, 2, 2, 'prop_str_3', NULL);
insert into item_attribute values (6, 2, 3, NULL, 2);
insert into item_attribute values (7, 3, 1, 'prop_str_4', NULL);
insert into item_attribute values (8, 3, 2, 'prop_str_2', NULL);
insert into item_attribute values (9, 3, 3, NULL, 1);
See if this works for you. It in essence does the same thing... Your first qualifier is that a given attribute name = 1 and string = 'prop_str_1', but then self-joins to attribute table again on same ID but second attribute and string
select
attr.*
from
item_attribute attr
JOIN item_attribute attr2
ON attr.item_id = attr2.item_id
and attr2.name = 2
and attr2.string_value = 'prop_str_2'
where
attr.name = 1
and string_value = 'prop_str_1'
I would also have an index on your table on (name, string_value, item_id) to increase performance of where and join conditions.
Given the following table:
CREATE TABLE #values (ID int, TYPE nchar(2), NUMBER int)
INSERT INTO #values values (1, 'A', 0)
INSERT INTO #values values (2, 'A', 0)
INSERT INTO #values values (3, 'B', 1)
INSERT INTO #values values (4, 'A', 1)
INSERT INTO #values values (5, 'B', 2)
SELECT * FROM #values
I would like to generate this table:
Id | T | N | COUNT
------------------
1 | A | 0 | 1000
2 | A | 0 | 1000
3 | B | 1 | 1001
4 | A | 1 | 1002
5 | B | 2 | 1003
How can I do this in T-SQL?
I've been fiddling with ROW_NUMBER() OVER(PARTITION BY) but this does not solve the problem, as it resets the count at each partition, which is not what I would like to do.
I think you're looking for dense_rank:
SELECT
ID,
TYPE,
NUMBER,
DENSE_RANK() over (order by TYPE, Number)
FROM #values
This produces
1 A 0 1
2 A 0 1
4 A 1 2
3 B 1 3
5 B 2 4