I need to update a field on a table to be true only if a matching row exists in another table, for all the rows where the column is currently null in the main table.
This is a description of what I want to achieve:
UPDATE [LenqReloaded].[dbo].[Enquiry] A
SET [ResponseLetterSent] = 1
WHERE [ResponseLetterSent] IS NULL
AND EXISTS
(
SELECT * FROM [LenqReloaded].[dbo].[Attachment] B
WHERE A.[EnquiryID] = B.[EnquiryID]
)
This isn't syntactically correct.
I can't code it via an IF EXISTS... statement because I don't have the [EnquiryID] without reading the data from the table.
How should I format my UPDATE statement?
You weren't far off...
UPDATE A
SET A.[ResponseLetterSent] = 1
FROM [LenqReloaded].[dbo].[Enquiry] A
WHERE A.[ResponseLetterSent] IS NULL
AND EXISTS ( SELECT * FROM [LenqReloaded].[dbo].[Attachment] B WHERE A.[EnquiryID] = B.[EnquiryID] )
You need to use a join in your update:
UPDATE [LenqReloaded].[dbo].[Enquiry] SET [ResponseLetterSent] = 1
FROM [LenqReloaded].[dbo].[Enquiry] A
join [LenqReloaded].[dbo].[Attachment] B on A.[EnquiryID] = B.[EnquiryID]
WHERE A.[ResponseLetterSent] IS NULL
This seems counterintuitive, but you need to establish a table alias in a From clause but use that alias in the Update Clause...
Update E Set
ResponseLetterSent = 1
From LenqReloaded.dbo.Enquiry E
Where ResponseLetterSent Is Null
And Exists (Select * From LenqReloaded.dbo.Attachment
Where EnquiryID = E.EnquiryID)
The thing you are missing is the 'from' clause, which is a t-sql extension - it is the only way to assign an alias to the updated table
update [lenqreloaded].[dbo].[enquiry]
set [responselettersent] = 1
from [lenqreloaded].[dbo].[enquiry] a
where [responselettersent] is null
and exists (
select *
from [lenqreloaded].[dbo].[attachment] b
where a.[enquiryid] = b.[enquiryid]
)
Related
How would my output change if I remove exists statement from the following query.
UPDATE AR_CRDT C
set (OPERATOR_ID,UPDT_TS) = ( SELECT AD.OPERATOR_ID,sysdate
FROM
(
Select A.*
FROM AR1_CUSTOMER_CREDIT A
)AD
WHERE AD.CREDIT_ID = C.CRDT_ID
)
where exists ( SELECT 1
FROM
(
Select A.*
FROM AR1_CUSTOMER_CREDIT A
)AD
WHERE AD.CREDIT_ID = C.CRDT_ID
);
If you remove the exists, then OPERATOR_ID and UPDT_TS would be set to NULL for rows where the conditions do not match.
Why would you write this with the extra subqueries?
UPDATE AR_CRDT C
SET (OPERATOR_ID, UPDT_TS) = (SELECT AD.OPERATOR_ID, sysdate
FROM AR1_CUSTOMER_CREDIT A
WHERE A.CREDIT_ID = C.CRDT_ID
)
WHERE EXISTS (SELECT 1
FROM AR1_CUSTOMER_CREDIT A
WHERE A.CREDIT_ID = C.CRDT_ID
);
The EXISTS currently causes the updates to AR_CRDT to be limited to those records where the AR_CRDT record is associated with an AR1_CUSTOMER_CREDIT record.
Removing that clause will mean that ALL records of AR_CRDT will be updated. Some will have values for the sub-query and some will be NULL where there is no link between AR_CRDT and AR1_CUSTOMER_CREDIT.
I'm trying to build a SQL command to update my table
Update a row in myProduct if it does not exists in table order, or if it exists, check in table order if the code is != 1 to update
UPDATE myProduct
SET statut = 3
WHERE
myProduct_id NOT IN (SELECT myProduct_id
FROM order
WHERE code != 1
AND myProduct.myProduct_id = order.myProduct_id)
OR NOT EXISTS IN (SELECT myProduct_id FROM order)
Thank you in advance
use the below code..
UPDATE p
SET statut = 3
FROM myProduct p
WHERE NOT EXISTS
(SELECT 1
FROM order o
WHERE code != 1
AND p.myProduct_id = 0.myProduct_id)
I believe the logic is: Update all rows where the corresponding row in order is not 1 (or none exists).
If so, you can do this with a simpler statement:
UPDATE myProduct p
SET statut = 3
WHERE NOT EXISTS (SELECT 1
FROM orders o
WHERE o.code = 1 AND p.myProduct_id = o.myProduct_id);
You don't specify the database, but the above is standard SQL.
Note: order is a really bad name for a table, because it is a SQL keyword. That is why I used orders instead of order.
UPDATE myProduct SET statut = 3
WHERE NOT EXISTS(SELECT 1 FROM order WHERE code != 1 AND myProduct.myProduct_id = order.myProduct_id )
I'm trying to migrate some tables into an existing table, I need to perform the updates only where DET_ATTACHMENT_ID equals DET_ATTACHMENT.ID, here's the query I have so far.
UPDATE DET_ATTACHMENT
SET attachment_type = 'LAB', -- being added by the query, to replace the table difference
payer_criteria_id = (
SELECT PAYER_CRITERIA_ID
FROM DET_LAB_ATTACHMENT
WHERE DET_LAB_ATTACHMENT.DET_ATTACHMENT_ID = DET_ATTACHMENT.ID)
WHERE exists(
SELECT DET_ATTACHMENT_ID
FROM DET_ATTACHMENT
JOIN DET_LAB_ATTACHMENT ON (ID = DET_ATTACHMENT_ID)
WHERE DET_ATTACHMENT_ID = DET_ATTACHMENT.ID
the problem with the existing query is that it's setting every row to have an attachment_type of "LAB", and nulling out the payer_criteria_id where it didn't match. What am I doing wrong?
The problem might be that your exists(...) predicate always evaluates to true, thus making the update run for all rows of det_attachment. Try it this way:
UPDATE DET_ATTACHMENT X
SET X.attachment_type = 'LAB',
X.payer_criteria_id = (
SELECT C.PAYER_CRITERIA_ID
FROM DET_LAB_ATTACHMENT C
WHERE C.DET_ATTACHMENT_ID = X.ID
)
WHERE
exists(
SELECT 1
FROM DET_ATTACHMENT A
JOIN DET_LAB_ATTACHMENT B
ON B.DET_ATTACHMENT_ID = A.ID
where B.det_attachment_id = X.id
)
;
I've created a junction table like this one:
http://imageshack.us/scaled/landing/822/kantotype.png
I was trying to figure out a query that could able to select some rows - based on the PokémonID - and then updating only the first or second row after the major "filtering".
For example:
Let's suppose that I would like to change the value of the TypeID from the second row containing PokémonID = 2. I cannot simply use UPDATE KantoType SET TypeID = x WHERE PokémonID = 2, because it will change both rows!
I've already tried to use subqueries containing IN,EXISTS and LIMIT, but with no success.
Its unclear what are your trying to do. However, you can UPDATE with JOIN like so:
UPDATE
SET k1.TypeID = 'somethng' -- or some value from k2
FROM KantoType k1
INNER JOIN
(
Some filtering and selecting
) k2 ON k1.PokémonID = k2.PokémonID
WHERE k1.PokémonID = 2;
Or: if you want to UPDATE only the two rows that have PokémonID = 2 you can do this:
WITH CTE
AS
(
SELECT *,
ROW_NUMBER() OVER(ORDER BY TypeID) rownum
FROM KantoType
WHERE PokemonID = 2
)
UPDATE c
SET c.TypeID = 5
FROM CTE c
WHERE c.rownum = 1;
SQL Fiddle Demo
I can suggest something like this if you just need to update a single line in your table:
UPDATE kantotype
SET
type = 2
WHERE pokemon = 2
AND NOT EXISTS (SELECT * FROM kantotype k2
WHERE kantotype.type > k2.type
AND kantotype.pokemon = k2.pokemon)
It would be easier to get the first or last item of the table if you had unique identifier field in your table.
Not sure even if you are trying to update the row with PokemenID =2 by doing a major filtering on TypeID... So just out of assumptiong (big one), you can give a try on Case
UPDATE yourtable a
LEFT JOIN youtable b on a.pokeid = b.pokeid
SET a.typeid = (CASE
WHEN a.typeid < b.typeid THEN yourupdatevalue
WHEN a.typeid > b.typeid THEN someothervalue
ELSE a.typeid END);
If you know the pokemon ID and the type id then just add both to the where clause of your query.
UPDATE KantoType
SET TypeID = x
WHERE PokémonID = 2
AND TypeID=1
If you don't know the type ID, then you need to provide more information about what you're trying to accomplish. It's not clear why you don't have this information.
Perhaps think about what is the unique identifier in your data set.
Evening all,
Actually, it's night. About 11pm. My brain is shutting down and I need a bit of help so I can finish and go home :)
I have two tables - table a and table b.
I need to update a field in table a with the value from a field in table b when two other fields match. The tables don't have a unique id for each record :(
Basically, I want to do this:
update a
set importantField =
(select b.importantfield
from b
where a.matchfield = b.matchfield
and a.matchfield2 = b.matchfield2
)
where a.matchfield = b.matchfield
and a.matchfield2 = b.matchfield2
Or at least... I think that's what I want to do...
Can someone help me out, please?
You can do this via a join in the update:
Update a
Set a.importantField = b.importantField
From a Join b
On a.matchfield = b.matchfield
And a.matchfield2 = b.matchfield2
Use:
UPDATE TABLE_A
SET importantField = (SELECT b.importantfield
FROM TABLE_B b
WHERE b.matchfield = matchfield
AND b.matchfield2 = matchfield2)
SQL Server doesn't support table aliases on the table being updated, but the above is a correlated query - those fields without the table alias b attached will serve values from TABLE_A because it doesn't have an alias.
The only issue beyond that is if there are multiple b.importantfield values for records with the matching records to TABLE_A. Use:
UPDATE TABLE_A
SET importantField = (SELECT TOP 1
b.importantfield
FROM TABLE_B b
WHERE b.matchfield = matchfield
AND b.matchfield2 = matchfield2)
..but you should use an ORDER BY as well or you'll get any random b.importantfield value.