Update statement in Oracle with joins - oracle

I have the below code in SQL Server:
UPDATE RH SET
--SELECT RH.economic_class ,
economic_class = C.economic_class
FROM dbo.tblRecHist RH
JOIN tblComp C ON RH.company_id = C.company_id
WHERE RH.company_id = #CompID
AND RH.rec_date = #RecDate
Which I have converted in Oracle to:
UPDATE tblRecHist
SET economic_class = (Select C.economic_class from tblComp C join tblRecHist
RH on RH.company_id = C.company_id)
WHERE RH.company_id = v_CompID
AND RH.rec_date = v_RecDate;
As this is a part of a big procedure I am unable to execute this independently.
So, my question is are both the logic correct? If not, what could be the possible change?

That logic won't work becuase your subquery will return more than one record. Instead of joining tblRecHist into your subquery, omit it and correlate the subquery with the current row of tblRecHist from the UPDATE.
UPDATE tblRecHist rh
SET economic_class = (Select C.economic_class
from tblComp C
WHERE C.company_id = RH.company_id )
WHERE RH.company_id = v_CompID
AND RH.rec_date = v_RecDate;
This assumes company_id is a unique key in tblComp.

Related

Oracle Update Statement Using a Join

I need some help with this query. It works fine in SSMS, but will not work in Oracle. How can I rewrite this so it will work in Oracle? I really appreciate the help.
UPDATE reservation_Daily_elements e
SET e.MARKET_CODE = 'PHEE',
e.ORIGIN_OF_BOOKING = 'DESKTOP'
FROM reservation_Daily_elements e
LEFT JOIN reservation_daily_element_name dn
ON e.resv_daily_el_seq = dn.resv_daily_el_seq
WHERE dn.RESV_NAME_ID IN ('3747957');
Commit;
How about MERGE?
merge into reservation_daily_elements e
using (select dn.resv_daily_el_seq
from reservatioin_daily_element_name dn
where dn.resv_name_id = '3747957'
) x
on (e.resv_daily_el_seq = x.resv_daily_el_seq)
when matched then update set
e.market_code = 'PHEE',
e.origin_of_booking = 'DESKTOP';
If it has to be UPDATE, then
update reservation_daily_elements e set
e.market_code = 'PHEE',
e.origin_of_booking = 'DESKTOP'
where exists (select null
from reservation_daily_element_name dn
where dn.resv_daily_el_seq = e.resv_daily_el_seq
and dn.resv_name = '3747957'
);
Btw, oracle supports updatable inline views, so you can use simple update (Select... From t1 join t2 on...) set... .
Also as I see your 'left join' is really 'inner join' because of the predicates in where clause.

UPDATE query is slow in combination with RETURNING INTO clause

I have update query which returns updated rows ID. Execution time of query is about 90 seconds. When i remove Returning clause, then execution time is 1ms.
Table update_table has 39000 rows.
Query updates 0 rows in this case. When updates 3 rows- execution time is same.
DECLARE
type intTable IS TABLE OF INTEGER;
idCol intTable;
BEGIN
UPDATE
update_table
SET
prop1 = 3, prop2 = NULL
WHERE EXISTS (
SELECT null FROM update_table f
INNER JOIN rel_table1 u ON f.ID= u.ID
INNER JOIN rel_table2 VP ON f.another_ID = VP.another_ID
WHERE (u.prop1 = 3)
AND VP.prop1 = 1
AND (u.prop2 = 75)
AND f.ID = update_table.ID
)
ReTURNING ID BULK COLLECT INTO idCol;
.
.
.
END;
Why returning clause slows down query?
A good part of using Oracle is knowing what is "supposed" to happen and what isn't.
Adding a RETURNING INTO clause is not "supposed" to make your update run more slowly. When something happens that isn't supposed to happen, check Oracle's support site to see whether it is a known bug.
In your case, it looks like you are encountering:
Bug 27131648 - SUB OPTIMAL PLAN ON UPDATE STATEMENT WITH RETURNING INTO
I am not sure if there is a patch, but there is a simple workaround: use the UNNEST hint. In your case, that would be:
UPDATE
update_table
SET
prop1 = 3, prop2 = NULL
WHERE EXISTS (
SELECT /*+ UNNEST */ null FROM update_table f
INNER JOIN rel_table1 u ON f.ID= u.ID
INNER JOIN rel_table2 VP ON f.another_ID = VP.another_ID
WHERE (u.prop1 = 3)
AND VP.prop1 = 1
AND (u.prop2 = 75)
AND f.ID = update_table.ID
)
ReTURNING ID BULK COLLECT INTO idCol;
I would recommend splitting it into two parts, first BULK COLLECT and next FORALL collected ID's, both extremely fast and you'll keep being able to further reference updated ID's from idCol.
DECLARE
type intTable IS TABLE OF INTEGER;
idCol intTable;
BEGIN
SELECT f.id
BULK COLLECT INTO idCol
FROM update_table f
INNER JOIN rel_table1 u ON f.ID= u.ID
INNER JOIN rel_table2 VP ON f.another_ID = VP.another_ID
WHERE (u.prop1 = 3)
AND VP.prop1 = 1
AND (u.prop2 = 75);
FORALL indx IN 1..idCol.COUNT
UPDATE update_table
SET prop1 = 3, prop2 = NULL
WHERE id = idCol(indx);
.
.
.
END;
I hope I helped!

Oracle Merge Into (Multiple Joined Tables) Update Set (Multiple Where Statements) Returns Invalid Column Specification

I am new to Oracle. I am trying to update the values of a table with the values from a SELECT DISTINCT statement using the MERGE INTO method. I want to update the values for a table based on what is in the USING table conditionally.
A quick diagram of what I am essentially going for is
MERGE
INTO update_table ut
USING
(SELECT DISTINCT
t1.column_1
,t2.column_2
FROM table_1 t1
INNER JOIN table_2 t2
ON t1.foreign_key = t2.primary_key) st
ON (ut.pk = st.column_1)
WHEN MATCH UPATE
SET(ut.update_column = st.column_2
WHERE st.column_1 = 1
AND st.column_2 = 1
,ut.update_column = st.column_2
WHERE st.column_1 = 2
AND st.column_2 = 2);
However, when I do so I get the INVALID COLUMN SPECIFICATION error on the line where I use SET. How can I work around this to successfully update the table, preferably in ANSI standard?
You can include the conditions that you have added in where clause in the selected column list in using clause itself. Like This. (Not tested. Your conditions in where clause were not appropriate)
MERGE
INTO update_table ut
USING (SELECT DISTINCT
t1.column_1 ,
CASE
WHEN t1.column_1 = 1
AND t2.column_2 = 1
THEN t2.column_1
WHEN t1.column_1 = 2
AND t2.column_2 = 2
THEN t2.column_2
END column_2
FROM
table_1 t1
INNER JOIN table_2 t2 ON t1.foreign_key = t2.primary_key
) st
ON (ut.pk = st.column_1)
WHEN MATCHED THEN
UPDATE SET ut.update_column = st.column_2 ;

How to update and set values based on multiple joins in select statment?

I want to update a column prtnum and revlvl in table invdtl based on value from select statment, here is the code
update invdtl set invdtl.prtnum = usr_prtmst_xref.prtnum,invdtl.revlvl =
usr_prtmst_xref.colnam ([select
invdtl.prtnum,usr_prtmst_xref.prtnum AS
crossref,invdtl.revlvl,aremst.arecod,aremst.fwiflg from invdtl
join usr_prtmst_xref
on usr_prtmst_xref.prtnum = usr_prtmst_xref.prtnum
join invsub
join invlod
join locmst
join aremst
on aremst.arecod = locmst.arecod
and aremst.wh_id = locmst.wh_id
on locmst.stoloc = invlod.stoloc
and locmst.wh_id = invlod.wh_id
on invlod.lodnum = invsub.lodnum
on invsub.subnum = invdtl.subnum where aremst.arecod = 'EXPR' or
aremst.fwiflg = '1' and rownum <2])
I want to copy two values prtnum and revlvl that are returned by select statement but there is some syntax issue.
There are a bunch of errors here:
The syntax for a multi-column update is basically
update blah
set ( col1, col2 ) = ( select x, y
from
...
)
The syntax for multiple joins is basically
from table1 t1
join table2 t2
on t1.col = t2.col
join table3 t2 on
t2.col = ...
Get ride of "[" and "]"
The predicate rownum<2 is probably to get around the message you received, something like "single row sub-query returns more than 1
row" Which this predicate "fixes" that problem, you are just getting
the first random row; probably not what you want. You probably need to
correlate the sub-query with the update
I would fix these basic syntax errors and try again.

Why sub SQL in FROM area can't be null?

select col_1,
col_2
from tbl_a A,
tbl_b B,
( select col_1,col_2 from tbl_c where clo_c_1 <> '1' ) C
where A.col_1 = B.col_1
and A.col_2 = B.col_2
and (A.col_2 = B.col_2
or C.col_2 = A.col_2);
My environment is Oracle,when I run this SQL,if the sub SQL C hasn't got a result,then the entire SQL returns NULL.Whereas if C has a result(not null) which fits other condions,there could be a result.Would somebody explain why sub SQL at the from area need to be not NULL?Thanks very much.
You need to bring yourself into the 90s and start using standard joins:
select col_1,
col_2
from tbl_a A
inner join
tbl_b B
on A.col_1 = B.col_1
and A.col_2 = B.col_2
left join
( select col_1,col_2 from tbl_c where clo_c_1 <> '1' ) C
on
C.col_2 = A.col_2
As a guess. I'm not entirely sure what your join conditions should be but that's my first attempt.
This is expected behaviour. When you join two result sets, you only want to get results where the join criteria is satisfied. If the criteria are not satisfied, you should get no results.
If I run the query "get me all the employees older than 65, and get their departments", if there are no employees older than 65, you would not expect to get any results, even if there are some departments in the database.
SELECT emp.name, dept.dept_name
FROM emp
JOIN dept
ON (emp.dept_no = dept.dept_no)
WHERE emp.age > 65;
As the others said, if you actually want to get rows regardless of whether the subquery has any results, you need to use an outer join.

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