I have an oracle query that uses a created table as part of the code. Every time I need to run a report I delete current data and import the new data I receive. This is one column of id's. I need to create a report on SSRS in which the user can input this data into said table as a parameter. I have designed a simple report that they can enter some of the id's into a parameter, but there may be times when they need to enter in a few thousand id's, and the report already runs long. Here is what the SSRS code currently says:
select distinct n.id, n.notes
from notes n
join (
select max(seq_num) as seqnum, id from notes group by id) maxresults
on n.id = maxresults.ID
where n.seq_num = maxresults.seqnum
and n.id in (#MyParam)
Is there a way to have MyParam insert data into a table I would join called My_ID, joining as Join My_Id id on n.id = id.id
I do not have permissions to create functions or procedures in the database.
Thank you
You may try the trick with MATERIALIZE hint which normally forces Oracle to create a temporary table :
WITH cte1 AS
( SELECT /*+ MATERIALIZE */ 1 as id FROM DUAL
UNION ALL
SELECT 2 DUAL
)
SELECT a.*
FROM table1 a
INNER JOIN cte1 b ON b.id = a.id
Related
I have two query that looks close to the same but Oracle have very different performance.
Query A
Create Table T1 as Select * from FinalView1 where CustomerID in ('A0000001','A000002')
Query B
Create Table T1 as Select * from FinalView1 where CustomerID in (select distinct CustomerID from CriteriaTable)
The CriteriaTable have 800 rows but all belongs to Customer ID 'A0000001' and 'A000002'.
This means the subquery: "select distinct CustomerID from CriteriaTable" also only returns the same two elements('A0000001','A000002') as manually entered in query A
Following is the query under the FinalView1
create or replace view FinalView1_20200716 as
select
Customer_ID,
<Some columns>
from
Table1_20200716 T1
INNER join Table2_20200716 T2 on
T1.Invoice_number = T2.Invoice_number
and
T1.line_id = T2.line_id
left join Table3_20200716 T3 on
T3.id = T1.Customer_ID
left join Table4_20200716 T4 on
T4.Shipping_ID = T1.Shipping_ID
left join Table5_20200716 Table5 on
Table5.Invoice_ID = T1.Invoice_ID
left join Table6_20200716 T6 on
T6.Shipping_ID = T4.Shipping_ID
left join First_Order first on
first.Shipping_ID = T1.Shipping_ID
;
Table1_20200716,Table2_20200716,Table3_20200716,Table4_20200716,Table5_20200716,Table6_20200716 are views to the corresponding table with temporal validity feature. For example
The query under Table1_20200716
Create or replace view Table1_20200716 as
select
*
from Table1 as for period of to_date('20200716,'yyyymmdd')
However table "First_Order" is just a normal table as
Following is the performance for both queries (According to explain plan):
Query A:
Cardinality: 102
Cost : 204
Total Runtime: 5 secs max
Query B:
Cardinality:27921981
Cost: 14846
Total Runtime:20 mins until user cancelled
All tables are indexed using those columns that used to join against other tables in the FinalView1. According to the explain plan, they have all been used except for the FirstOrder table.
Query A used uniquue index on the FirstOrder Table while Query B performed a full scan.
For query B, I was expecting the Oracle will firstly query the sub-query get the result into the in operator, before executing the main query and therefore should only have minor impact to the performance.
Thanks in advance!
As mentioned from my comment 2 days ago. Someone have actually posted the solution and then have it removed while the answer actually work. After waiting for 2 days the So I designed to post that solution.
That solution suggested that the performance was slow down by the "in" operator. and suggested me to replace it with an inner join
Create Table T1 as
Select
FV.*
from
FinalView1 FV
inner join (
select distinct
CustomerID
from
CriteriaTable
) CT on CT.customerid = FV.customerID;
Result from explain plan was worse then before:
Cardinality:28364465 (from 27921981)
Cost: 15060 (from 14846)
However, it only takes 17 secs. Which is very good!
Let me explain the question.
I have two tables, which have 3 columns with same data tpyes. The 3 columns create a key/ID if you like, but the name of the columns are different in the tables.
Now I am creating queries with these 3 columns for both tables. I've managed to independently get these results
For example:
SELECT ID, FirstColumn, sum(SecondColumn)
FROM (SELECT ABC||DEF||GHI AS ID, FirstTable.*
FROM FirstTable
WHERE ThirdColumn = *1st condition*)
GROUP BY ID, FirstColumn
;
SELECT ID, SomeColumn, sum(AnotherColumn)
FROM (SELECT JKM||OPQ||RST AS ID, SecondTable.*
FROM SecondTable
WHERE AlsoSomeColumn = *2nd condition*)
GROUP BY ID, SomeColumn
;
So I make a very similar queries for two different tables. I know the results have a certain number of same rows with the ID attribute, the one I've just created in the queries. I need to check which rows in the result are not in the other query's result and vice versa.
Do I have to make temporary tables or views from the queries? Maybe join the two tables in a specific way and only run one query on them?
As a beginner I don't have any experience how to use results as an input for the next query. I'm interested what is the cleanest, most elegant way to do this.
No, you most probably don't need any "temporary" tables. WITH factoring clause would help.
Here's an example:
with
first_query as
(select id, first_column, ...
from (select ABC||DEF||GHI as id, ...)
),
second_query as
(select id, some_column, ...
from (select JKM||OPQ||RST as id, ...)
)
select id from first_query
minus
select id from second_query;
For another result you'd just switch the tables, e.g.
with ... <the same as above>
select id from second_query
minus
select id from first_query
I'm practically new in using oracle and I bumped into a blocker. Below is the query that I created based on what I have researched online to update multiple columns of a table with values from a nested join statement.
UPDATE
(
SELECT
A.COLUMN1 OLD_COLUMN1,
BC.COLUMN1 NEW_COLUMN1,
A.BALANCE OLD_COLUMN2,
BC.COLUMN2_MIN NEW_COLUMN2,
A.COLUMN3 OLD_COLUMN3,
BC.COLUMN3 NEW_COLUMN3
FROM TABLE_A A
INNER JOIN
(
SELECT B.TWWID,
B.ITEMDATE,
B.COLUMN2_MIN,
C.COLUMN3,
C.COUNTRYID,
C.COLUMN1
FROM TABLE_B B
LEFT OUTER JOIN TABLE_C C
ON TO_CHAR(B.ID) = TO_CHAR(C.ID)
) BC
ON A.ID = BC.ID
AND A.DATE = BC.DATE
)ABCUPDATE
SET ABCUPDATE.OLD_COLUMN1 = ABCUPDATE.NEW_COLUMN1,
ABCUPDATE.OLD_COLUMN2 = ABCUPDATE.NEW_COLUMN2,
ABCUPDATE.OLD_COLUMN3 = ABCUPDATE.NEW_COLUMN3;
Selecting the sub-query returns the expected results but when I run the update script as a whole an error is returned.
ORA-01779: cannot modify a column which maps to a non key-preserved
table
Can anyone please explain why I encounter this error and what adjustments can I do to the script to make it work?
Thanks in advance!
I have a query like below - table names etc. changed for keeping the actual data private
SELECT inv.*,TRUNC(sysdate)
FROM Invoice inv
WHERE (inv.carrier,inv.pro,inv.ndate) IN
(
SELECT carrier,pro,n_dt FROM Order where TRUNC(Order.cr_dt) = TRUNC(sysdate)
)
I am selecting records from Invoice based on Order. i.e. all records from Invoice which are common with order records for today, based on those 3 columns...
Now I want to select Order_Num from Order in my select query as well.. so that I can use the whole thing to insert it into totally seperate table, let's say orderedInvoices.
insert into orderedInvoices(seq_no,..same columns as Inv...,Cr_dt)
(
SELECT **Order.Order_Num**, inv.*,TRUNC(sysdate)
FROM Invoice inv
WHERE (inv.carrier,inv.pro,inv.ndate) IN
(
SELECT carrier,pro,n_dt FROM Order where TRUNC(Order.cr_dt) = TRUNC(sysdate)
)
)
?? - how to do I select that Order_Num in main query for each records of that sub query?
p.s. I understand that trunc(cr_dt) will not use index on cr_dt (if a index is there..) but I couldn't select records unless I omit the time part of it..:(
If the table ORDER1 is unique on CARRIER, PRO and N_DT you can use a JOIN instead of IN to restrict your records, it'll also enable you to select whatever data you want from either table:
select order.order_num, inv.*, trunc(sysdate)
from Invoice inv
join order ord
on inv.carrier = ord.carrier
and inv.pro = ord.pro
and inv.ndate = ord.n_dt
where trunc(order.cr_dt) = trunc(sysdate)
If it's not unique then you have to use DISTINCT to deduplicate your record set.
Though using TRUNC() on CR_DT will not use an index on that column you can use a functional index on this if you do need an index.
create index i_order_trunc_cr_dt on order (trunc(cr_dt));
1. This is a really bad name for a table as it's a keyword, consider using ORDERS instead.
Recently I fixed the some bug: there was rownum in the join condition.
Something like this: left join t1 on t1.id=t2.id and rownum<2. So it was supposed to return only one row regardless of the “left join”.
When I looked further into this, I realized that I don’t understand how Oracle evaluates rownum in the "left join" condition.
Let’s create two sampe tables: master and detail.
create table MASTER
(
ID NUMBER not null,
NAME VARCHAR2(100)
)
;
alter table MASTER
add constraint PK_MASTER primary key (ID);
prompt Creating DETAIL...
create table DETAIL
(
ID NUMBER not null,
REF_MASTER_ID NUMBER,
NAME VARCHAR2(100)
)
;
alter table DETAIL
add constraint PK_DETAIL primary key (ID);
alter table DETAIL
add constraint FK_DETAIL_MASTER foreign key (REF_MASTER_ID)
references MASTER (ID);
prompt Disabling foreign key constraints for DETAIL...
alter table DETAIL disable constraint FK_DETAIL_MASTER;
prompt Loading MASTER...
insert into MASTER (ID, NAME)
values (1, 'First');
insert into MASTER (ID, NAME)
values (2, 'Second');
commit;
prompt 2 records loaded
prompt Loading DETAIL...
insert into DETAIL (ID, REF_MASTER_ID, NAME)
values (1, 1, 'REF_FIRST1');
insert into DETAIL (ID, REF_MASTER_ID, NAME)
values (2, 1, 'REF_FIRST2');
insert into DETAIL (ID, REF_MASTER_ID, NAME)
values (3, 1, 'REF_FIRST3');
commit;
prompt 3 records loaded
prompt Enabling foreign key constraints for DETAIL...
alter table DETAIL enable constraint FK_DETAIL_MASTER;
set feedback on
set define on
prompt Done.
Then we have this query :
select * from master t
left join detail d on d.ref_master_id=t.id
The result set is predictable: we have all the rows from the master table and 3 rows from the detail table that matched this condition d.ref_master_id=t.id.
Result Set
Then I added “rownum=1” to the join condition and the result was the same
select * from master t
left join detail d on d.ref_master_id=t.id and rownum=1
The most interesting thing is that I set “rownum<-666” and got the same result again!
select * from master t
left join detail d on d.ref_master_id=t.id and rownum<-666.
Due to the result set we can say that this condition was evaluated as “True” for 3 rows in the detail table. But if I use “inner join” everything goes as supposed to be.
select * from master t
join detail d on d.ref_master_id=t.id and rownum<-666.
This query doesn’t return any row,because I can't imagine rownum to be less then -666 :-)
Moreover, if I use oracle syntax for outer join, using “(+)” everything goes well too.
select * from master m ,detail t
where m.id=t.ref_master_id(+) and rownum<-666.
This query doesn’t return any row too.
Can anyone tell me, what I misunderstand with outer join and rownum?
ROWNUM is a pseudo-attribute of result sets, not of base tables. ROWNUM is defined after rows are selected, but before they're sorted by an ORDER BY clause.
edit: I was mistaken in my previous writeup of ROWNUM, so here's new information:
You can use ROWNUM in a limited way in the WHERE clause, for testing if it's less than a positive integer only. See ROWNUM Pseudocolumn for more details.
SELECT ... WHERE ROWNUM < 10
It's not clear what value ROWNUM has in the context of a JOIN clause, so the results may be undefined. There seems to be some special-case handling of expressions with ROWNUM, for instance WHERE ROWNUM > 10 always returns false. I don't know how ROWNUM<-666 works in your JOIN clause, but it's not meaningful so I would not recommend using it.
In any case, this doesn't help you to fetch the first detail row for each given master row.
To solve this you can use analytic functions and PARTITION, and combine it with Common Table Expressions so you can access the row-number column in a further WHERE condition.
WITH numbered_cte AS (
SELECT *, ROW_NUMBER() OVER (PARTITION BY t.id ORDER BY d.something) AS rn
FROM master t LEFT OUTER JOIN detail d ON d.ref_master_id = t.id
)
SELECT *
FROM numbered_cte
WHERE rn = 1;
if you want to get the first three values from the join condition change the select statement like this.
select *
from (select *
from master t left join detail d on d.ref_master_id=t.id)
where rownum<3;
You will get the required output. Take care on unambigiously defined column names when using *
Let me give an absolute answer which u can run directly with out making any changes to the code.
select *
from (select t.id,t.name,d.id,d.ref_master_id,d.name
from master t left join detail d on d.ref_master_id=t.id)
where rownum<3;
A ROWNUM filter doesn't make any sense in a join, but it isn't being rejected as invalid.
The explain plan will either include the ROWNUM filter or exclude it. If it includes it, it will apply the filter to the detail table after applying the other join condition(s). So if you put in ROWNUM=100 (which will never be satisfied) all the detail rows are excluded and then the outer join kicks in.
If you put in ROWNUM=1 it seems to drop the filter.
And if you query
with
a as (select rownum a_val from dual connect by level < 10),
b as (select rownum*2 b_val from dual connect by level < 10)
select * from a left join b on a_val < b_val and rownum in (1,3);
you get something totally weird.
It probably should be rejected as an error, so expect nonsensical things to happen