I am trying to understand the merge search condition and have come across the following problem.
Table1
id groupid description
-------------------------
1 10 Good
2 20 Better
Table2
id groupid description
-------------------------
1 10 Very Good
1 20 Much Better
I intend to merge the source (table1) to target (table2) on the id present in both but only groupid = 20 present in target table.
Here is what I am writing
Merge table1 source
Using table2 target ON (target.id = source.id AND target.groupid = 20)
When Matched
Then update
set target.description = source.description
The output I am expecting is
Table2
id groupid description
-------------------------
1 10 Very Good
1 20 Good
But I am not 100% sure of the ON clause (merge search condition) with multiple conditions of checking target.id = source.id and target.groupid = 20. Is the result always predictable and matching the expectation above in these multiple conditions ? Or is predictability a question here and should I be adding target.groupId = 20 in the "when matched AND" condition ?
It looks like your join is wrong. You are either needing to join on the GROUPID or your data is incorrect.
JOINING ON GROUP
create table #table1 (id int, groupid int, description varchar(64))
create table #table2 (id int, groupid int, description varchar(64))
insert into #table1 values
(1,10,'Good'),
(2,20,'Better')
insert into #table2 values
(1,10,'Very Good'),
(1,20,'Much Better')
Merge #table2 t
Using #table1 s
ON (t.groupid = s.groupid AND t.groupid = 20)
When Matched
Then update
set t.description = s.description;
select * from #table2
drop table #table2
drop table #table1
Otherwise, there isn't any way to correlate "better" from ID = 2 to a row where ID = 1. This goes against your original join condition on the ID column.
BASED OFF EDITED EXPECTED OUTPUT
create table #table1 (id int, groupid int, description varchar(64))
create table #table2 (id int, groupid int, description varchar(64))
insert into #table1 values
(1,10,'Good'),
(2,20,'Better')
insert into #table2 values
(1,10,'Very Good'),
(1,20,'Much Better')
Merge #table2 t
Using #table1 s
ON (t.id = s.id) --you could also put the and t.groupid = 20 here...
When Matched and t.groupid = 20
Then update
set t.description = s.description;
select * from #table2
drop table #table2
drop table #table1
Related
I have two tables where TableA has latest data and TableB has some old data. I want to update TableB's data if it matches id with TableA and if doesn't match insert new row in TableB.
I got a solution from stackOverflow
begin tran
if exists (select * from t with (updlock,serializable) where pk = #id)
begin
update t set hitCount = hitCount+1
where pk = #id
end
else
begin
insert t (pk, hitCount)
values (#id, 1)
end
commit tran
But it seems I need to pass #id each time, may be I am not getting it in the correct way. I have hundreds of row to update/insert from tableA.
Think relationally.
SQL Server always operates sets. A single row is just a set of 1 row.
Here is a simple example of two step update - insert operations
create table #tableA(id int, [year] int, updated_value int)
insert #tableA(id,[year],updated_value)
values
(1,1990,85),
(2,1991,70),
(3,1992,80)
create table #tableB(id int, [year] int, score int)
insert #tableB(id,[year],score)
values
(1,1990,50),
(4,1995,20)
update #tableA set
updated_value=b.score
from #tableA a
inner join #tableB b on a.id=b.id --inner is important
insert #tableA(id,[year],updated_value)
select b.id,b.[year],b.score
from #tableB b
left join #tableA a on a.id=b.id --left is important
where a.id is null -- and this line too
select * from #tableA
If you wish you can combine update and insert in a single merge operation.
merge #tableA as tgt
using #tableB as src
on src.id=tgt.id
when matched then
update set updated_value=src.score
when not matched then
insert(id,[year],updated_value)
values(id,[year],score)
; -- semicoloumn is required
select * from #tableA
This might be a stupid question, but I am not a DBA and kind of stuck with this issue. I have an application that trickles down all effects (asdf) under an applied ID (IDParent).
The data tables are setup like this:
Data Tables
3rd Data Table
I want to write a query that when using IDChild it will reference that entry's IDParent to get the parent ID while referencing it as an IDChild. For example for the data entry starting at 116 I want to use the parent ID (124) and get 321 in T1. I want to use this to get the RandoName associated with RandoID for all of the entries that has a parent ID of 321.
Right now I am using a script something like:
Select t.[NAME]
From T2 tv
Inner join T3 t on t.RandoID = tv.RandoId
Where
tv.IDChild = T1.IDChild OR tv.IDChild = T1.IDParent
but I'm not sure how to get the whole applied hierarchy.
This would yield something like this:
Resulting Query
PS. I can not change the tables/db schema. But maybe I can add one to do all the referencing? Please tell me what you think.
EDIT I'm sorry I forgot about this other stupid table that RandoID uses which contains the name of the RandoID. I am trying to get the name of RandoID
I think a loop could help you.
Try this:
CREATE TABLE #t1 (IDChild Int, IDParent Int);
CREATE TABLE #t2 (RandoID NVARCHAR(10) , IDChild Int);
CREATE TABLE #RandoName (RandoID NVARCHAR(10), RandoName VARCHAR(50));
INSERT INTO #t1 VALUES (321, NULL), (123,321),(124,123),(116,124)
INSERT INTO #t2 VALUES ('asdf', 123)
INSERT INTO #RandoName VALUES ('asdf', 'something')
SELECT ROW_NUMBER() OVER (ORDER BY (SELECT 100)) [RowNum], a.IDChild a, a.IDParent b, b.IDChild c INTO #t3 FROM #t1 a
LEFT OUTER JOIN #t1 b ON b.IDParent = a.IDChild
DECLARE #rownum INT;
DECLARE cbcursor CURSOR for Select RowNum FROM #t3;
OPEN cbcursor;
Fetch Next from cbcursor into #rownum
WHILE ##FETCH_STATUS = 0
BEGIN
UPDATE #t3
SET c = (SELECT b from #t3 where RowNum = #rownum-1)
WHERE RowNum = #rownum
Fetch Next from cbcursor into #rownum;
END;
Close cbcursor;
Deallocate cbcursor;
SELECT a,b,t2.RandoID, r.RandoName FROM #t3
LEFT OUTER JOIN #t2 t2 on t2.IDChild = #t3.c OR t2.IDChild = #t3.b OR t2.IDChild = #t3.a
LEFT OUTER JOIN #RandoName r on t2.RandoID = r.RandoID
This is what I get:
If you have any changes in your tables, like more records for T2, this script should be modified.
Using recursion:
declare #t table (IDc int , Idp int)
insert into #t
values
(321,null)
,(123,321)
,(124,123)
,(116,124)
declare #t2 table (RandoID varchar(10), IDChild int)
insert into #t2
values('asdf',123)
;with cte as
(
select anchor = IDChild
,ParentOrSelf = IDc
,RandoID
,RandomName
from #t
cross join (select RandoID,RandoName from #t2 t2 join #t3 t3 on t2.RandoID=t3.RandoID) crossed
where IDc=#anchor
union all
select t2.IDChild
,IDc
, t2.RandoID,RandomName
from #t t
cross join (select RandoID,RandoName from #t2 t2 join #t3 t3 on t2.RandoID=t3.RandoID) t2
join cte on cte.ParentOrSelf = t.Idp
)
select IDc
, cte.RandoID,cte.RandomName
from #t t
left join cte on t.IDc = cte.ParentOrSelf
Results:
IDc RandoID
321 NULL
123 asdf
124 asdf
116 asdf
I want to update each row of table1->keyField based on table2 value
Table1
Id|keyField
1|test_500
2|test_501
3|test_501
500,501 are primary key of and my another table2
Table2
Id|value
500|A
501|B
502|C
I have tried something like
update table1 set keyField=(select value from table2 where id=substring(expression))
but my select return multiple statement so unable to run the query.
any help or direction please?
You can use the syntax like this
UPDATE table1 SET keyField = Table2.Value
FROM table1 INNER JOIN table2
ON table1.Id = substring(expression))
If I get it right, this might be what you need:
UPDATE T1 SET
keyField = T2.Value
FROM
Table1 AS T1
INNER JOIN Table2 AS T2 ON T2.id = SUBSTRING(T1.keyField, 6, 100)
Careful when comparing substring result with an numeric value, might get a conversion error.
Try this code (necessary notes are in comments below):
--generate some sample data (the same as you provided)
declare #table1 table (id int, keyField varchar(10))
insert into #table1 values (1,'test_500'),(2,'test_501'),(3,'test_502')
declare #table2 table (id int, value char(1))
insert into #table2 values (500,'A'),(501,'B'),(502,'C')
--in case you want to see tables first
--select * from #table1
--select * from #table2
--here you extract the number in first table in keyField column and match it with ID from second table, upon that, you update first table
update #table1 set keyField = value from #table2 [t2]
where cast(right(keyfield, len(keyfield) - charindex('_',keyfield)) as int) = [t2].id
select * from #table1
i have written a merge Statement where i am facing trouble to delete the data basing on Where Clause Condition.
Let me explain my scenario Clearly
For example i have inserted Data from Source to Target based on Date Key Condition.Take an Instance 10 Records Inserted.
For example some changes in the records and it has been updated through the Merge Statement .
For the Same Date key based on Conditions now three records has came and need to be inserted and rest should be deleted for that Date Key.
How i need to proceed on this before 10 records are not getting deleted and new records adding for that one
My Example Code :
DELETE FROM #Table1
CREATE TABLE #Table1
(ID INT ,Name VARCHAR(30),DATEKEY INT)
INSERT INTO #Table1 (ID,Name,DATEKEY)VALUES (1,'Mohan',20131231)
INSERT INTO #Table1 (ID,Name,DATEKEY)VALUES (2,'Raj',20131231)
INSERT INTO #Table1 (ID,Name,DATEKEY)VALUES (3,'Majjaa',20131231)
INSERT INTO #Table1 (ID,Name,DATEKEY)VALUES (4,'Majjaa',20131231)
CREATE TABLE #Table2
(ID INT ,Name VARCHAR(30),DATEKEY INT)
DECLARE #i_DateKey INT
SET #i_DateKey = '20131231'
MERGE #Table2 AS T
USING (
SELECT pdp.ID
,pdp.Name
,pdp.DATEKEY
FROM #Table1 AS pdp
WHERE (
pdp.DateKey = #i_DateKey
OR #i_DateKey IS NULL
)
) AS S
ON T.ID = S.ID
AND T.DateKey = S.DateKey
AND T.NAME = S.NAME
WHEN MATCHED
THEN
UPDATE
SET T.NAME = S.NAME
WHEN NOT MATCHED BY TARGET
THEN
INSERT
VALUES (
S.ID
,S.Name
,S.DateKey
)
WHEN NOT MATCHED BY SOURCE
THEN
DELETE ;
Now the target table will be loaded with Rows now if i send the another row for Same Date key then it need to be deleted all the 4 rows and reload the new Row if the new row is same then need to update
i think this is one big mistake,
ON T.ID = S.ID --i am not sure about this
AND T.DateKey = S.DateKey
AND T.NAME = S.NAME -- remove this because this when matched then update will do what ?
WHEN MATCHED
THEN
UPDATE
SET T.NAME = S.NAME
I am looking to select the id of a record from #table1 when that record is the only record in that table and is not currently linked in #t1Tot2 to a particular id from another table.
The following query below works, but I am wondering if there is a better way. It is setup to currently to return 55 the id of the only record added to table #table1. Inserting another record into #table1 would cause it to return no records ( good ), and linking #t2id in #t1Tot2 would make it return none as well ( good ). Is there a better way? Thanks.
DECLARE #t2id INT
SET #t2id = 1 --Record to link to
DECLARE #table1 TABLE
(
t1id int
)
DECLARE #t1Tot2 TABLE
(
t1id INT,
t2id int
)
INSERT INTO #table1
( t1id )
VALUES ( 55 -- t1id - int
)
--Will cause the query below to return no records because of having more than 1 record to be linked to
-- INSERT INTO #table1
-- ( t1id )
--VALUES ( 2 -- t1id - int
-- )
--Will cause the query below to return no records because of already being linked to the t1id
--INSERT INTO #t1Tot2
--( t1id, t2id )
--VALUES ( 55, -- t1id - int
--#t2id -- t2id - int
--)
SELECT MAX(a.t1id)
FROM #table1 a
LEFT JOIN #t1Tot2 b ON a.t1id = b.t1id AND b.t2id = 1
HAVING COUNT(1) = 1 AND SUM( CASE WHEN b.t2id IS NULL THEN 0 ELSE 1 END ) = 0
--declare #table1 table (t1id int)
--declare #t1Tot2 table (t1id int)
select a.t1id
from #table1 a
where (select count(*) from (select top 2 * from #table1) x) = 1
and not exists (
select * from #t1Tot2 b
where b.t1id = a.t1id)
select a.aid
from a
left outer join b on a.bid=b.bid
where b.bid is null
group by a.aid
having count(*) = 1
should work as well sql server specific sql btw.