Currently, I have some SQL queries which looks like this:
Drop Table X;
Create Table X(id INTEGER);
Insert Into X
select ..
from..
where a.name = GIVENNAME;
Select SUM(..)
from ..
..
order by date desc;
And I want to put all these into a SQL Function, where I can choose the Parameter "GIVENNAME" when I call the function.
Is there a way to make this possible?
I would know how to do it in JSON/Java, but I have really no clue how to make it as a Function in SQL (using Oracle).
Edit:
After pointing out some things, I want to add my current code:
DROP TABLE TEMPTABLE;
CREATE TABLE TEMPTABLE
(mitID INTEGER);
INSERT INTO TEMPTABLE
select m.mitid
from mitarbeiter m
inner join abteilungen a on m.abt = a.abtid
where a.abtname = #GIVENNAME;
select SUM(g.kosten)
from gehaelter g
left outer join gehaelter k
on g.mitarbeiter = k.mitarbeiter
and g.vondatum < k.vondatum
where k.mitarbeiter is null AND g.mitarbeiter in (select * from TEMPTABLE)
order by g.vondatum desc;
I'm currently more interested in a working solution than a nice & clean one
Fortunately you can have both:
create or replace function get_sum_kosten
( p_givenname in abteilungen.abtname%type )
return number
as
return_value number;
begin
select SUM(g.kosten)
into return_value
from gehaelter g
left outer join gehaelter k
on g.mitarbeiter = k.mitarbeiter
and g.vondatum < k.vondatum
where k.mitarbeiter is null
AND g.mitarbeiter in (select m.mitid
from mitarbeiter m
inner join abteilungen a on m.abt = a.abtid
where a.abtname = P_GIVENNAME
)
;
return return_value;
end;
Possible? Yes. Recommended? No.
For any DDL, you'd have to use dynamic SQL (EXECUTE IMMEDIATE). If queries are complex, those commands will be difficult to maintain.
INSERT is a DML, but you can't use it in a function, unless it is an autonomous transaction (and you'll have to commit (or rollback) within the function).
If it were a procedure, you'd - at least - avoid the last problem I mentioned. If you're returning something, use an OUT parameter.
Can't you use a (global) temporary table, instead? Create it once, use it many times. I understand that your code might be very complex and maybe it really can't fit into a single SELECT statement, but you should - at least - try to do that job in an Oracle spirit (i.e. it is not MS SQL Server).
example of procedure
https://www.sitepoint.com/stored-procedures-mysql-php/
like this
DELIMITER $$
CREATE PROCEDURE `avg_sal`(out avg_sal decimal)
BEGIN
select avg(sal) into avg_sal from salary;
END
Related
I have to write a stored procedure that starts copying the data from a table 'company' into a staging table 'company_stg' if no records for that date are present in it.
I have the following code :
CREATE OR REPLACE
PACKAGE BODY PKG_TEST AS
PROCEDURE SP_BILLING AS
BEGIN
EXECUTE IMMEDIATE 'SELECT * FROM COMPANY INTO COMPANY_STG
WHERE NOT EXISTS (SELECT * FROM COMPANY_STG WHERE AS_OF_DATE = "2023-02-08")';
END;
END PKG_TEST;
I AM GETTING THE ERROR "SQL COMMAND NOT PROPERLY ENDED"
company * company_stg have as_of_date as a column. rest all are same.
please help me with this
I have also tried
if not exists (SELECT * FROM COMPANY_STG WHERE AS_OF_DATE = "2023-02-08")
then
select from company into company_stg
So many things look bad in that piece of code...
First, why use dynamic SQL execute immediate? It's best to avoid dynamic SQL as much as possible because it leads to runtime errors and requires pretty much instrumentation so that it may be debugged. Generally you use dynamic SQL when you do not know beforehand the name of a table it will operate on, which is not the case for you. You definitely know you have to work with tables COMPANY and COMPANY_STG. Is it not so?
Then, it doesn't look like you have read the manual to see an insert select.
When you insert into a table, it's best to give the list of columns into which you actually insert data. If one alters that table and adds one or more than one column, the insert which does not have the list of columns will crash.
Thus, to insert into COMPANY_STG data from COMPANY, the SQL should look like below:
insert into company_stg(
... ---- here should be the list of columns you insert data into
)
select
... --- here should the source columns you are willing to insert
from company c
where not exists (
select 1
from company_stg cs
where cs.as_of_date= --- what is the condition??? I did not understand
)
;
You have not given the structures for those tables, so that I can't give you the columns to select and to insert into. Nor did I really understand what the condition for inserting data should be.
SELECT does not perform a copy and SELECT * FROM COMPANY INTO COMPANY_STG is not valid syntax. You want to use an INSERT statement to do that (and check if there is any row first):
CREATE OR REPLACE PACKAGE BODY PKG_TEST AS
PROCEDURE SP_BILLING
AS
BEGIN
DECLARE
v_staged_count NUMBER;
BEGIN
SELECT 1
INTO v_staged_count
FROM COMPANY_STG
WHERE AS_OF_DATE = DATE '2023-02-08'
FETCH FIRST ROW ONLY; -- We don't care how many rows so stop after finding
-- the first one.
-- Stop as rows have been found.
RETURN;
EXCEPTION
WHEN NO_DATA_FOUND THEN
-- Continue
NULL;
END;
INSERT INTO company_stg
SELECT *
FROM COMPANY;
END;
END PKG_TEST;
/
fiddle
I'm given quite a huge table My_Table and a user-defined collection Picture_Arr as an input usually having 5-10 rows declared as:
TYPE Picture_Rec IS RECORD (
seq_no NUMBER,
task_seq NUMBER);
TYPE Picture_Arr IS TABLE OF Picture_Rec;
In MS SQL I would normally write something like:
DECLARE #Picture_Arr TABLE (seq_no INT, task_seq INT)
SELECT M.*
FROM My_Table M
INNER JOIN #Picture_Arr A
ON M.seq_no = A.seq_no AND M.task_seq = A.task_seq
But I can't get my head around how to re-write the same code in Oracle as Picture_Arr is not a table. As some tutorials state that I could've looped through My_Table and compare keys, but is it efficient in Oracle or is there another way of doing that?
Perhaps this is what you are looking for. It is a bit complicated to understand what is the desired output, and whether the data of the record is stored somewhere or not
create type Picture_Rec as object(
seq_no NUMBER,
task_seq NUMBER);
)
/
create type Picture_Tab as table of Picture_Rec
/
create or replace function get_picture_list
return Picture_Tab
is
l_pic Picture_Tab;
begin
select Picture_Rec ( seqno, taskseq )
bulk collect into l_pic
from your_table; -- the table you have these records
return l_pic;
end;
/
Then you run
SELECT M.*
FROM My_Table M
JOIN TABLE ( get_picture_list() ) p
ON M.seq_no = p.seq_no AND M.task_seq = p.task_seq
I am actually training in oracle SQL basics and I have created a trigger that looks like this one (it works!):
create or replace TRIGGER insert_refereenation
BEFORE INSERT OR UPDATE ON Game
FOR EACH ROW
DECLARE
v_nation_id NUMBER(4) := '';
v_nationname VARCHAR2(100) := '';
BEGIN
SELECT Nation_id
INTO v_nation_id
FROM referre
WHERE referee_id= :new.referee_id;
SELECT Name
INTO v_nationname
FROM Nation
WHERE Nation_id = v_nation_id;
:NEW.referee_nation_name:= v_nationname;
END;
This trigger works fine but I have two simple questions:
Is it possible to write the result from the second SELECT right into the: NEW.referee_nation_name field? So I wouldn´t need the second variable.
Do you see other things which can get optimized?
You could use a join so that you have only one query instead of two, and use the :new.column_name directly in the into clause:
SELECT n.name
INTO :new.referee_nation_name
FROM referee r
JOIN nation n ON r.nation_id = n.nation_id
WHERE r.referee_id = :new.referee_id;
My problem isn't overly complicated, but I am a newbie to PL/SQL.
I need to make a selection from a COMPANIES table based on certain conditions. I then need to loop through these and convert some of the fields into a different format (I have created functions for this), and finally use this converted version to join to a reference table to get the score variable I need. So basically:
select id, total_empts, bank from COMPANIES where turnover > 100000
loop through this selection
insert into MY_TABLE (select score from REF where conversion_func(MY_CURSOR.total_emps) = REF.total_emps)
This is basically what I am looking to do. It's slightly more complicated but I'm just looking for the basics and how to approach it to get me started!
Here's the basic syntax for cursor loops in PL/SQL:
BEGIN
FOR r_company IN (
SELECT
ID,
total_emps,
bank
FROM
companies
WHERE
turnover > 100000
) LOOP
INSERT INTO
my_table
SELECT
score
FROM
ref_table
WHERE
ref.total_emps = conversion_func( r_company.total_emps )
;
END LOOP;
END;
/
You don't need to use PL/SQL to do this:
insert into my_table
select score
from ref r
join companies c
on r.total_emps on conversion_func(c.total_emps)
where c.turnover > 100000
If you have to do this in a PL/SQL loop as asked, then I'd ensure that you do as little work as possible. I would, however, recommend bulk collect instead of the loop.
begin
for xx in ( select conversion_func(total_emps) as tot_emp
from companies
where turnover > 100000 ) loop
insert into my_table
select score
from ref
where total_emps = xx.tot_emp
;
end loop;
end;
/
For either method you need one index on ref.total_emps and preferably one on companies.turnover
LV_id number;
Cursor CR_test Is
select t.id
from table1 t
where t.foo = p_foo
order by t.creation_date;
Open CR_test;
Fetch CR_test
Into LV_id;
Close CR_test;
or this one :
select x.id
from(select t.id
from table1 t
where t.foo=p_foo
order by t.creation_date) x
where rownum = 1
Both above make similar result but i need known about which one is more efficient!
This is Tom Kyte's mantra:
You should do it in a single SQL statement if at all possible.
If you cannot do it in a single SQL Statement, then do it in PL/SQL.
If you cannot do it in PL/SQL, try a Java Stored Procedure.
If you cannot do it in Java, do it in a C external procedure.
If you cannot do it in a C external routine, you might want to seriously think about why it is you need to do it…
http://tkyte.blogspot.com/2006/10/slow-by-slow.html
Easiest way to find out in this case is to test your queries.
Make sure to test this yourself, indexes and data in your table may produce different results with your table.
Without any index, it looks like there is a better approach using analytic function DENSE_RANK:
SELECT MIN(id) KEEP (DENSE_RANK FIRST ORDER BY creation_date)
INTO lv_id
FROM table1
WHERE foo = p_foo;
I used the following code to test the time consumed by your queries (execute this block several times, results may vary):
DECLARE
p_foo table1.foo%TYPE := 'A';
lv_id table1.id%TYPE;
t TIMESTAMP := SYSTIMESTAMP;
BEGIN
FOR i IN 1 .. 100 LOOP
-- Query here
END LOOP;
dbms_output.put_line(SYSTIMESTAMP - t);
END;
Results:
Using cursor, fetching first row:
2.241 s
Using query with ROWNUM:
1.483 s
Using DENSE_RANK:
1.168 s