Given this code (pseudo)
MERGE INTO ...
(SELECT ... FROM ...) ...
ON (...)
WHEN NOT MATCHED THEN
INSERT (...) VALUES (...);
//This is Oracle Apex code
apex_application.g_unrecoverable_error := true;
htp.init();
owa_util.redirect_url('f?p=111:11:&APP_SESSION.::NO:::');
How would add a condition so that when it doesn't match it, I need to run this line of code:
apex_application.g_notification := 'My error';
I am not sure what to do to make it work. I tried some ELSE and additional WHEN statements but it doesn't seem to work.
As far as I am aware you will not be able to extend the MERGE statement in this way. You can take a count of of table being inserted into before and after to determine whether any rows fell into the NOT MATCHED section and got inserted.
Put your logic in an IF statement using that count.
In a MERGE statement depending on the ON cond
you issue a UPDATE and optionally DELETE if MATCHED
you issue a INSERT if NOT MATRCHED
Your apex code can not be part of the MERGE statement. You have to figure out a different strategy for it.
Related
I am working on an If Exists Then Update, Else Insert statement in SQL Server and have 2 questions.
First, I was hoping to be able to debug my statement by effectively having it perform two steps:
If Exists (select.....)
Print 'Record already exists'
UPDATE Tab set Col....
Which fails. Is there a way to get both statements to execute or can I only have one result when If Exists returns TRUE? I tried a comma after the PRINT command but that made no difference.
Second, my If Exists query returns one record (for now). But, running my UPDATE without a WHERE clause causes every record in the Table to be changed. I thought the UPDATE would operate only on the records returned by the If Exists test. Do I need to specify a WHERE clause in my UPDATE statement, much like I would if I had no If Exists test?
The sintax that you need should be the next:
if exists (select ... _your_condition_)
begin
Print 'Record already exists'
UPDATE Tab set Col....
end
else
begin
Print 'New record'
INSERT into Tab ....
end
Remark that without begin/end blocks, the if applies just the immediate next sentence, so the update would be done always in your example.
This is just one answer to one part of your question, which is quite misleading. If your WHERE filter has some relationship with the check that you are performing in the "if exists" sentence, we should know it exactly to know if there is a better way to resolve your query.
please help
IF EXISTS(SELECT * FROM MERC_ADM_VERSION )then UPDATE MERC_ADM_VERSION SET
VER_VALEUR = 20150409 WHERE VER_CLE = 'MEAD' ELSE INSERT INTO MERC_ADM_VERSION
('VER_VALEUR', 'VER_CLE') VALUES (20150409, 'MEAD');
ORA-00900: Invalid SQL statement
Remove the single quotes from the columns in the insert statement.
Instead of
('VER_VALEUR', 'VER_CLE')
It should be
(VER_VALEUR, VER_CLE)
Your question is quite unclear as to what you are trying to do. However, my best interpretation is you are looking for an oracle merge statement. Below is an example based on assumptions I made on the little information you provided. You are most likely looking for a MERGE statement. This allows you to perform a single operation that can either update or insert based on your criteria.
Also, you appear to be using a date, but in number format. I did nothing to address this due to lack of any table definition. You may still have problems with it.
MERGE
INTO merc_adm_version TARGET -- The table you want to update/insert into
USING (SELECT 20150409 as ver_valeur, 'MEAD' as ver_cle FROM dual) SOURCE -- The source of the data
ON (TARGET.ver_cle = SOURCE.ver_cle) -- How to try and match records between source and target
WHEN MATCHED THEN UPDATE SET ver_valeur = 20150409 -- When there is a match, how to update
WHEN NOT MATCHED THEN INSERT (ver_cle, ver_valeur) -- When there is not a match, how to insert
VALUES ('MEAD', 20150409);
Consider the following:
merge into T t1
using (select ID,Col1 from T where ID = 123) t2
on 1 = 0
when not matched then insert (Col1) values (t2.Col1);
Cominig from a programming background, to me this translates to:
"Evaluate false (i.e. 1 = 0), and when it is false (i.e. all the time), insert."
Is it not possible to just omit the match condition?
Is it because of my select's where condition that I'm confused here? Should this condition be moved to the on?
NOTE:
Due to restrictions with output, I cannot use insert. I need to output the results of this merge into a temporary table for reasons outside of the scope of what I'm asking.
In the answer you've linked to in the comments, as I've hopefully made clear, we are abusing the MERGE statement.
The query you've shown here could trivially be replaced by:
insert into T(Col1) select Col1 from T where ID = 123
However, if you want to be able to add an OUTPUT clause, and that OUTPUT clause needs to reference both the newly inserted data and data from the source table, you're not allowed to write such a clause on an INSERT statement.
So, we instead use a MERGE statement, but not for its intended purpose. The entire purpose is to force it to perform an INSERT and write our OUTPUT clause.
If we examine the documentation for MERGE, we see that the only clause in which we can specify to perform an INSERT is in the WHEN NOT MATCHED [BY TARGET] clause - in both the WHEN MATCHED and WHEN NOT MATCHED BY SOURCE clauses, our only options are to UPDATE or DELETE.
So, we have to write the MERGE such that matching always fails - and the simplest way to do that is to say that matching should occur when 1 = 01 - which, hopefully, is never.
1Since SQL Server doesn't support boolean literals
I am using APEX collections to store some values and pass them between pages in Oracle Application Express 4.2.3.
I would like to then perform an update statement on a table called "project" with the values from the collection.
My code so far is as follows:
update project
SET name=c.c002,
description=c.c007,
start_date=c.c004,
timeframe=c.c005,
status=c.c009
FROM
apex_collections c
WHERE
c.collection_name = 'PROJECT_DETAILS_COLLECTION'
and id = :p14_id;
where :p14_id is the value of a page item.
However, I am getting the following error:
ORA-00933: SQL command not properly ended
Anyone have any idea on how to approach this?
Thanks!
The UPDATE syntax you are using is not valid in Oracle; it does not allow you to use FROM in the way you are attempting.
The simplest way to do this in Oracle would with a subquery:
update project
set (name, description, start_date, timeframe, status) =
(select c.c002, c.c007, c.c004, c.c005, c.c009
FROM
apex_collections c
WHERE
c.collection_name = 'PROJECT_DETAILS_COLLECTION'
)
WHERE
id = :p14_id
;
Note that if the subquery returns no rows, the columns in the target table will be updated to NULL; this could be avoided by adding a similar EXISTS condition in the predicate for the update. It could also be avoided by using a MERGE statement instead of an UPDATE.
If the subquery returns multiple rows, the statement will throw an error. It looks like tthat should not be the case here.
I want to write a update SQL statement, but one conidtion of this statement is the result from a select SQL statement, and I also want to return the result of the select SQL statement.
Like this: update ... set ... where id = (select id from ...)
I want to return the value of id back.
Does anybody know how should I do this?
Thanks in advance!
I don't believe that's possible in one statement. Update then query (select) the new value, or query the value first, and then submit an update.
Alternative would be a stored procedure on the database, which executes the multiple queries and returns the result for you.
This is not possible in all Java database frameworks that I know. Probably you need to separate your query and update in Java.
I don't see any problem in using a subselect in a WHERE clause of an update statement.
For the second request, getting back the value of id, I know this is possible in DB2, and maybe others implement that syntax too:
SELECT id FROM FINAL TABLE (
update ... set ... where id = (select id from ...)
)
This works also for INSERT and DELETE statements. (See the documentation.)
Update statements won't return the updated datasets. The select in that case would be a subselect that isn't directly accessible.
You'd thus have to use at least two queries:
select the ids you want
call the update query passing the previously selected ids as a parameter