I have a SQL MERGE statement that does an UPDATE if a value exists (and an INSERT if it does). I'd like to record the last few "historical" values in the row when an UPDATE happens, sort of like this:
MERGE into desttable as dest
USING sourcetable as src
on src.ref = dest.ref
WHEN MATCHED THEN
UPDATE SET dest.oldvalue3=dest.oldvalue2,
dest.oldvalue2=dest.oldvalue1,
dest.oldvalue1=dest.value,
dest.value=src.newvalue
WHEN NOT MATCHED THEN
INSERT ...
... so essentially, the existing "value" is shuffled down to "oldvalue1", "oldvalue1" becomes "oldvalue2" etc. However, when I run this, every column gets set to "value" - the UPDATE statement is obviously setting all the fields at once. Is there any way to achieve what I'm trying to do?
You can left outer join desttable in the using clause and use columns from desttable as source to the update.
MERGE INTO desttable AS dest
USING (SELECT s.ref,
s.newvalue,
d.oldvalue2,
d.oldvalue1,
d.value
FROM sourcetable AS s
LEFT OUTER JOIN desttable AS d
ON s.ref = d.ref) AS src
ON src.ref = dest.ref
WHEN MATCHED THEN
UPDATE SET dest.oldvalue3=src.oldvalue2,
dest.oldvalue2=src.oldvalue1,
dest.oldvalue1=src.value,
dest.value=src.newvalue
;
https://data.stackexchange.com/stackoverflow/q/114412/
Related
I have data flowing into one table from multiple other tables lets say: Table_A
Then I have a Merge stored proc that takes data from table A merges it with Table B.
However, something doesn't seem to be right. If i truncate and load the data it works fine, but if i dont truncate and load, and just fetch the query by eachh hour I get the error message saying
Msg 8672, Level 16, State 1, Procedure Merge_Table_A, Line 4 [Batch Start Line 0]
The MERGE statement attempted to UPDATE or DELETE the same row more than once. This happens when a target row matches more than one source row. A MERGE statement cannot UPDATE/DELETE the same row of the target table multiple times. Refine the ON clause to ensure a target row matches at most one source row, or use the GROUP BY clause to group the source rows.
How can I overcome this?
I want to be able to incrementally load the data and not do truncate loads, but at the same time have a stored proc that updates or inserts or doesnt care if the row already exists.
Seems you have duplicate rows in your target table which are loaded from your previous runs.
Note: Matching in a Merge does not consider the rows inserted (even duplicate) while running the Merge itself.
Below is my repro example with a sample data:
Table1: Initial data
Table2: Taget table
Merge Statement:
MERGE tb2 AS Target
USING tb1 AS Source
ON Source.firstname = Target.firstname and
Source.lastname = Target.lastname
-- For Inserts
WHEN NOT MATCHED BY Target THEN
INSERT (firstname, lastname, updated_date)
VALUES (Source.firstname, Source.lastname, source.updated_date)
-- For Updates
WHEN MATCHED THEN UPDATE SET
Target.updated_date = Source.updated_date
-- For Deletes
WHEN NOT MATCHED BY Source THEN
DELETE;
When Merge is executed, it inserts all data without any errors.
New data in tb1:
When I run the Merge statement, it gives me the same error as yours.
As a workaround using one of the below options,
Add additional conditions if possible in the ON clause to uniquely identify the data.
Remove the duplicates from the source and merge the data into tb2 as below.
--temp table
drop table if exists #tb1;
select * into #tb1 from (
select *, row_number() over(partition by firstname, lastname order by firstname, lastname, updated_date desc) as rn from tb1) a
where rn = 1
MERGE tb2 AS Target
USING #tb1 AS Source
ON Source.firstname = Target.firstname and
Source.lastname = Target.lastname
-- For Inserts
WHEN NOT MATCHED BY Target THEN
INSERT (firstname, lastname, updated_date)
VALUES (Source.firstname, Source.lastname, source.updated_date)
-- For Updates
WHEN MATCHED THEN UPDATE SET
Target.updated_date = Source.updated_date
-- For Deletes
WHEN NOT MATCHED BY Source THEN
DELETE;
Data merged into tb2 successfully.
I have two tables table_1 and table_2. After inserting some data into table_1(insert not in the example below), it gives Auto_Increment ID to table_1. Then I need to put this new generated ID into table_2 in NOT MATCHED section.
I am trying to use T-SQL's MERGE, to UPDATE table if data already exists (if matched) or INSERT INTO table if there is no such data(not matched), but in second case insert by using one column selected from another table.
Here is what I have already tried:
MERGE
INTO table_2 WITH (HOLDLOCK) AS target
USING (SELECT
'42' AS person_id
,2 AS skill_id
) AS source
(person_id,skill_id )
ON (target.person_id = source.person_id
AND target.skill_id = source.skill_id)
WHEN MATCHED
THEN UPDATE
SET skill_lvl=4,already_have=0
WHEN NOT MATCHED
--section below doesn't work,because insert inside MERGE has to be without select (?)
THEN INSERT (person_id, skill_id, skill_lvl,already_have)
SELECT 42, id,3,1 FROM table_1;
Not matched section gives me an error that he waits values or default, but it seems kind of tricky to select with values or default.
Edit_1
Insert query to table_1 (happens before previous MERGE. Both MERGES within one loop):
MERGE
INTO table_1 WITH (HOLDLOCK) AS target
USING (SELECT
'skill_1' AS skill_name
) AS source
(skill_name)
ON (target.skill_name = source.skill_name)
WHEN NOT MATCHED
THEN INSERT (category_id,skill_name) values (0,'skill_1');
this query in the loop, compares skill_names, if name is not inside this table_1, it inserts this value. Then compare next skill_name and so on. ID's are generating automatically after inserting.
How to insert multiple rows in a merge in SQL?
I'm using a MERGE INSERT and I'm wondering is it possible to add two rows at the same time? Under is the query I have written, but as you can see, I want to insert both boolean for IsNew, also when it is not matched, I want to add a row for IsNew = 1 and one IsNew = 0.
How can I achieve this?
MERGE ITEMS AS TARGET
USING #table AS SOURCE
ON T.[ID]=S.ID
WHEN MATCHED THEN
UPDATE SET
T.[Content] = S.[Content],
WHEN NOT MATCHED THEN
INSERT (ID, Content, TIME, IsNew)
VALUES (ID, TEXT, GETDATE(), 1),
You can't do this directly with a merge statement, but there is a simple solution.
The merge statement <merge_not_matched> clause (which is the insert...values|default values) clause can only insert one row on the target table for each row in the source table.
This means that for you to enter two rows for each match, you simply need to change the source table - in this case, it's as simple as a cross join query.
However the <merge_matched> clause requires that only a single row from the source can match any single row from the target - or you will get the following error:
The MERGE statement attempted to UPDATE or DELETE the same row more than once. This happens when a target row matches more than one source row. A MERGE statement cannot UPDATE/DELETE the same row of the target table multiple times. Refine the ON clause to ensure a target row matches at most one source row, or use the GROUP BY clause to group the source rows.
To solve this problem you will have to add a condition to the when match to make sure only one row from the source table updates the target table:
MERGE Items AS T
USING (
SELECT Id, Text, GetDate() As Date, IsNew
FROM #table
-- adding one row for each row in source
CROSS JOIN (SELECT 0 As IsNew UNION SELECT 1) AS isNewMultiplier
) AS S
ON T.[ID]=S.ID
WHEN MATCHED AND S.IsNew = 1 THEN -- Note the added condition here
UPDATE SET
T.[Content] = S.[Text]
WHEN NOT MATCHED THEN
INSERT (Id, Content, Time, IsNew) VALUES
(Id, Text, Date, IsNew);
You can see a live demo on rextester.
With all that being said, I would like to refer you to another stackoverflow post that offers a better alternative then using the merge statement.
The author of the answer is a Microsoft MVP and an SQL Server expert DBA, you should at least read what he has to say.
It seems you can't achieve this using a merge statement. It may be better for you to split the two into separate queries for update and insert.
For example:
UPDATE ITEMS SET ITEMS.ID = #table.ID FROM ITEMS INNER JOIN #table ON ITEMS.ID = #table.ID
INSERT INTO ITEMS (ID, Content, TIME, IsNew) SELECT (ID, TEXT, GETDATE(), 1) FROM #table
INSERT INTO ITEMS (ID, Content, TIME, IsNew) SELECT (ID, TEXT, GETDATE(), 0) FROM #table
This will insert both rows as desired, mimicking your merge statement. However, your update statement won't do much - if you're matching based on ID, then it's impossible for you to have any IDs to update. If you wanted to update other fields, then you could change it like this:
UPDATE ITEMS SET ITEMS.Content = #table.TEXT FROM ITEMS INNER JOIN #table ON ITEMS.ID = #table.ID
I have an insert Query and inserting data using SELECT query and certain joins between tables.
While running that query, it is giving error "String or binary data would be truncated".
There are thousands of rows and multiple columns I am trying to insert in that table.
So it is not possible to visualize all data and see what data is throwing this error.
Is there any specific way to identify which column is throwing this error? or any specific record not getting inserted properly and resulted into this error?
I found one article on this:
RareSQL
But this is when we insert data using some values and that insert is one by one.
I am inserting multiple rows at the same time using SELECT statements.
E.g.,
INSERT INTO TABLE1 VALUES (COLUMN1, COLUMN2,..) SELECT COLUMN1, COLUMN2,.., FROM TABLE2 JOIN TABLE3
Also, in my case, I am having multiple inserts and update statements and even not sure which statement is throwing this error.
You can do a selection like this:
select TABLE2.ID, TABLE3.ID TABLE1.COLUMN1, TABLE1.COLUMN2, ...
FROM TABLE2
JOIN TABLE3
ON TABLE2.JOINCOLUMN1 = TABLE3.JOINCOLUMN2
LEFT JOIN TABLE1
ON TABLE1.COLUMN1 = TABLE2.COLUMN1 and TABLE1.COLUMN2 = TABLE2.COLUMN2, ...
WHERE TABLE1.ID = NULL
The first join reproduces the selection you have been using for the insert and the second join is a left join, which will yield null values for TABLE1 if a row having the exact column values you wanted to insert does not exist. You can apply this logic to your other queries, which were not given in the question.
You might just have to do it the hard way. To make it a little simpler, you can do this
Temporarily remove the insert command from the query, so you are getting a result set out of it. You might need to give some of the columns aliases if they don't come with one. Then wrap that select query as a subquery, and test likely columns (nvarchars, etc) like this
Select top 5 len(Col1), *
from (Select col1, col2, ... your query (without insert) here) A
Order by 1 desc
This will sort the rows with the largest values in the specified column first and just return the rows with the top 5 values - enough to see if you've got a big problem or just one or two rows with an issue. You can quickly change which column you're checking simply by changing the column name in the len(Col1) part of the first line.
If the subquery takes a long time to run, create a temp table with the same columns but with the string sizes large (like varchar(max) or something) so there are no errors, and then you can do the insert just once to that table, and run your tests on that table instead of running the subquery a lot
From this answer,
you can use temp table and compare with target table.
for example this
Insert into dbo.MyTable (columns)
Select columns
from MyDataSource ;
Become this
Select columns
into #T
from MyDataSource;
select *
from tempdb.sys.columns as TempCols
full outer join MyDb.sys.columns as RealCols
on TempCols.name = RealCols.name
and TempCols.object_id = Object_ID(N'tempdb..#T')
and RealCols.object_id = Object_ID(N'MyDb.dbo.MyTable)
where TempCols.name is null -- no match for real target name
or RealCols.name is null -- no match for temp target name
or RealCols.system_type_id != TempCols.system_type_id
or RealCols.max_length < TempCols.max_length ;
I having the scenario of loading the data from source table to target table. If the data from source is not present in target, then i need to insert. If it is present in the target table already, then update the status of the row to 'expire' and insert the column as new row. I used Merge query to do this. I can do insert if not exists and i can do update also. But while trying to insert when matched, it says insert not allowed in 'when matched' clause.
Please help me.. Thanks in advance
If you want to perform multiple actions for a single row of source data, you need to duplicate that row somehow.
Something like the following (making up table names, etc):
;WITH Source as (
SELECT Col1,Col2,Col3,t.Dupl
FROM SourceTable,(select 0 union all select 1) t(Dupl)
)
MERGE INTO Target t
USING Source s ON t.Col1 = s.Col1 and s.Dupl=0 /* Key columns here */
WHEN MATCHED THEN UPDATE SET Expired = 1
WHEN NOT MATCHED AND s.Dupl=1 THEN INSERT (Col1,Col2,Col3) VALUES (s.Col1,s.Col2,s.Col3);
You always want the s.Dupl condition in the not matched branch, because otherwise source rows which don't match any target rows would be inserted twice.
From the example you posted as a comment, I'd change:
MERGE target AS tar USING source AS src ON src.id = tar.id
WHEN MATCHED THEN UPDATE SET D_VALID_TO=#nowdate-1, C_IS_ACTIVE='N', D_LAST_UPDATED_DATE=#nowdate
WHEN NOT MATCHED THEN INSERT (col1,col2,col3) VALUES (tar.col1,tar.col2,tar.col3);
into:
;WITH SourceDupl AS (
SELECT id,col1,col2,col3,t.Dupl
FROM source,(select 0 union all select 1) t(Dupl)
)
MERGE target AS tar USING SourceDupl as src on src.id = tar.id AND Dupl=0
WHEN MATCHED THEN UPDATE SET D_VALID_TO=#nowdate-1, C_IS_ACTIVE='N', D_LAST_UPDATED_DATE=#nowdate
WHEN NOT MATCHED AND Dupl=1 THEN INSERT (col1,col2,col3) VALUES (src.col1,src.col2,src.col3);
I've changed the values in the VALUES clause, since in a NOT MATCHED branch, the tar table doesn't have a row to select values from.
Check out one of those many links:
Using SQL Server 2008's MERGE Statement
MERGE on Technet
Introduction to MERGE statement
SQL Server 2008 MERGE
Without actually knowing what your database tables look like, we cannot be of more help - you need to read those articles and figure out yourself how to apply this to your concrete situation.