I have a table, inside there is a field called x, the x field contain value of '1+2', '1+3' etc, how to get these value and calculate it and save into another field?
For simple arithmetic expressions - and depending on your Oracle version - you could use xmlquery to evaluate. Note that / has special meaning in xml, the operator for division is the keyword div - so you need a replace in case you may have forward slashes in the arithmetic expression. (If you don't have any divisions, you can simplify the query by removing the call to replace.)
Here is an example - including the test data at the top, in a with clause (not part of the solution!)
with
test_data (str) as (
select '1 + 3' from dual union all
select '3 * 5 - 2' from dual union all
select '2/4*6' from dual union all
select '3 * (1 - 3)' from dual
)
select str, xmlquery(replace(str, '/', ' div ') returning content).getNumberVal()
as evaluated_expression
from test_data;
STR EVALUATED_EXPRESSION
----------- --------------------
1 + 3 4
3 * 5 - 2 13
2/4*6 3
3 * (1 - 3) -6
If you only have valid PL/SQL arithmetic expressions in your formulas, then you can use EXECUTE IMMEDIATE to evaluate them.
For this, you'll need to create a function:
create or replace function eval_expression(p_expression in varchar2)
return number is
query varchar2(100);
result number;
begin
query := 'select ' || p_expression || ' from dual';
execute immediate query
into result;
return result;
end eval_expression;
Then you can use this function in UPDATE query:
update t
--val is another field
set t.val = eval_expression(t.x)
Naturally, with EXECUTE IMMEDIATE this query won't be extremely efficient, but it'll work. Also, with dynamic queries we're going into unsafe territory, so make sure that you don't have malicious code among your formulas.
Also, see "Evaluate Expression" on Ask TOM. Tom Kyte used a slightly more civilized approach (dbms_sql package) and created a package with a single variable support.
If the case you have mentioned needs to be considered then I will suggest you use the following query:
select
xmlquery('3+4'
returning content
).getNumberVal()
from
dual;
If More operators are involved except division then the aforementioned query will work but if the division operator is also involved then you must have to replace "/" with " div " keyword. Something like the following:
select
xmlquery(
replace( '20/5', '/', ' div ')
returning content
).getNumberVal()
from
dual;
Now, you can use it in your update statement or anywhere else.
update tab
set tab.result_column_name = xmlquery(t.your_expr_column_name
returning content
).getNumberVal()
update tab
set tab.result_column_name = xmlquery(
replace( t.your_expr_column_name, '/', ' div ')
returning content
).getNumberVal()
Demo
Cheers!!
I have a problem which I can't solve. Maybe you have an idea about how to solve it.
I do have a given parameter-table like this:
P_VALUE P_NAME
----------- ----------
X85 A_03
XH1 A_04
XH2 A_04
XH3 A_04
C84 A_05
As you can see there are parameters with multiple entries. At the moment this parameters are used in this way:
SELECT * FROM tablex
WHERE code IN (SELECT p_value
FROM parameter_table
WHERE p_name LIKE 'A_04');
As the query is very big these parameter sub-select are used very often. I was trying to implement a function in Oracle to get my parameters. This works very fine as long as there is just 1 row per parameter. When I want to use it in "IN-Statements", it won't work because functions just return a single value.
--WORKS
SELECT * FROM tablex
WHERE code = (f_get_param('A_03'));
--DOES NOT WORK
SELECT * FROM tablex
WHERE code IN (f_get_param('A_04'));
Please note that I need it for plain SQL statements, so procedures won't work as they are just good for PL/SQL.
I would be really thankful for good ideas or help!
Use collections. Here you have an example http://www.adp-gmbh.ch/ora/plsql/coll/return_table.html
Technically you can achieve using the function this way but doing this will cause index not to be used on code column on tablex and may affect performance .Using function index you can reduce performance impact
CREATE OR REPLACE FUNCTION f_get_param(p_value1 IN VARCHAR2,p_name1 in VARCHAR2) return NUMBER
DETERMINISTIC
IS
l_count NUMBER;
BEGIN
select count(1) into l_count from parameter_table where p_value =p_value1
and p_name=p_name1;
if l_count > 0
then
return 1;
else
return 0;
end if;
end f_get_param;
AND use the select statement like this
SELECT * FROM tablex
WHERE f_get_param(code,'A_04')=1;
EDIT 1:-
Also to reduce the performance impact in database 10.2 and greater If the parameter_table is static you can use the DETERMINISTIC clause in the Function to say that the function returns the same value if called with same parameters every time
Please find the link on the article about using functions in SELECT statement
--DOES NOT WORK
SELECT * FROM tablex
WHERE code IN (f_get_param('A_04'));
-- Try this
SELECT * FROM tablex
WHERE code IN (select * from TABLE(f_get_param('A_04')));
You have to "CAST" a collection onto SQL TABLE.
Also when you use cast you can also use inner joint:
SELECT * FROM tablex join TABLE(f_get_param('A_04') using (code);
I think - generally - your problem is called "Dynamic where clause". Try to search some articles about it on AskTom.
I think the actual solution to your problem is to simply join the two tables and create the appropriate indexes rather than invoking a PL/SQL function at all:
SELECT x.* FROM tablex x, parameter_table p
WHERE x.code = p.p_value
AND p.p_name LIKE '%A_04%';
Note that you also have a semantic error in your LIKE clause. You're not using the % sign therefore your LIKE 'A_04' is just the same as = 'A_04'
I have a function that returns a value and displays a similarity between tracks, i want the returned result to be ordered by this returned value, but i cannot figure out a way on how to do it, here is what i have already tried:
CREATE OR REPLACE PROCEDURE proc_list_similar_tracks(frstTrack IN tracks.track_id%TYPE)
AS
sim number;
res tracks%rowtype;
chosenTrack tracks%rowtype;
BEGIN
select * into chosenTrack from tracks where track_id = frstTrack;
dbms_output.put_line('similarity between');
FOR res IN (select * from tracks WHERE ROWNUM <= 10)LOOP
SELECT * INTO sim FROM ( SELECT func_similarity(frstTrack, res.track_id)from dual order by sim) order by sim; //that's where i am getting the value and where i am trying to order
dbms_output.put_line( chosenTrack.track_name || '(' ||frstTrack|| ') and ' || res.track_name || '(' ||res.track_id|| ') ---->' || sim);
END LOOP;
END proc_list_similar_tracks;
/
declare
begin
proc_list_similar_tracks(437830);
end;
/
no errors are given, the list is just presented unsorted, is it not possible to order by a value that was returned by a function? if so, how do i accomplish something like this? or am i just doing something horribly wrong?
Any help will be appreciated
In the interests of (over-)optimisation I would avoid ordering by a function if I could possibly avoid it; especially one that queries other tables. If you're querying a table you should be able to add that part to your current query, which enables you to use it normally.
However, let's look at your function:
There's no point using DBMS_OUTPUT for anything but debugging unless you're going to be there looking at exactly what is output every time the function is run; you could remove these lines.
The following is used only for a DBMS_OUTPUT and is therefore an unnecessary SELECT and can be removed:
select * into chosenTrack from tracks where track_id = frstTrack;
You're selecting a random 10 rows from the table TRACKS; why?
FOR res IN (select * from tracks WHERE ROWNUM <= 10)LOOP
Your ORDER BY, order by sim, is ordering by a non-existent column as the column SIM hasn't been declared within the scope of the SELECT
Your ORDER BY is asking for the least similar as the default sort order is ascending (this may be correct but it seems wrong?)
Your function is not a function, it's a procedure (one without an OUT parameter).
Your SELECT INTO is attempting to place multiple rows into a single-row variable.
Assuming your "function" is altered to provide the maximum similarity between the parameter and a random 10 TRACK_IDs it might look as follows:
create or replace function list_similar_tracks (
frstTrack in tracks.track_id%type
) return number is
sim number;
begin
select max(func_similarity(frstTrack, track_id)) into sim
from tracks
where rownum <= 10
;
return sim;
end list_similar_tracks;
/
However, the name of the function seems to preclude that this is what you're actually attempting to do.
From your comments, your question is actually:
I have the following code; how do I print the top 10 function results? The current results are returned unsorted.
declare
sim number;
begin
for res in ( select * from tracks ) loop
select * into sim
from ( select func_similarity(var1, var2)
from dual
order by sim
)
order by sim;
end loop;
end;
/
The problem with the above is firstly that you're ordering by the variable sim, which is NULL in the first instance but changes thereafter. However, the select from DUAL is only a single row, which means you're randomly ordering by a single row. This brings us back to my point at the top - use SQL where possible.
In this case you can simply SELECT from the table TRACKS and order by the function result. To do this you need to give the column created by your function result an alias (or order by the positional argument as already described in Emmanuel's answer).
For instance:
select func_similarity(var1, var2) as function_result
from dual
Putting this together the code becomes:
begin
for res in ( select *
from ( select func_similarity(variable, track_id) as f
from tracks
order by f desc
)
where rownum <= 10 ) loop
-- do something
end loop;
end;
/
You have a query using a function, let's say something like:
select t.field1, t.field2, ..., function1(t.field1), ...
from table1 t
where ...
Oracle supports order by clause with column indexes, i.e. if the field returned by the function is the nth one in the select (here, field1 is in position 1, field2 in position 2), you just have to add:
order by n
For instance:
select t.field1, function1(t.field1) c2
from table1 t
where ...
order by 2 /* 2 being the index of the column computed by the function */
I just implemented the ODCIAggregate Interface to create a custom aggregation function. It works quite well and fast, but I would like it to do a little something more. I have a statement going like this:
SELECT SomeId, myAggregationFunction(Item) FROM
(
SELECT
Foo.SomeId,
SomeType(Foo.SomeValue, Foo.SomeOtherValue) AS Item
FROM
Foo
ORDER BY Foo.SomeOrderingValue
)
GROUP BY SomeId;
My problem is that items aren't passed to the ODCIAggregateIterate function of my implementation in the same order that my inner (ordered) SELECT returns them.
I've Googled around and didn't find any Oracle-provided way to do so. Has any of you experimented a similar problem based on that requirement?
Thanks!
Have you considered using COLLECT instead of data cartridge?
At least for string aggregation, the COLLECT method is simpler and much faster. It does make your SQL a little weirder though.
Below is an example using just simple string concatenation.
--Create a type
create or replace type sometype as object
(
someValue varchar2(100),
someOtherValue varchar2(100)
);
--Create a nested table of the type.
--This is where the performance improvement comes from - Oracle can aggregate
--the types in SQL using COLLECT, and then can process all the values at once.
--This significantly reduces the context switches between SQL and PL/SQL, which
--are usually more expensive than the actual work.
create or replace type sometypes as table of sometype;
--Process all the data (it's already been sorted before it gets here)
create or replace function myAggregationFunction(p_sometypes in sometypes)
return varchar2 is
v_result varchar2(4000);
begin
--Loop through the nested table, just concatenate everything for testing.
--Assumes a dense nested table
for i in 1 .. p_sometypes.count loop
v_result := v_result || ',' ||
p_sometypes(i).someValue || '+' || p_sometypes(i).someOtherValue;
end loop;
--Remove the first delimeter, return value
return substr(v_result, 2);
end;
/
--SQL
select someId
,myAggregationFunction
(
cast
(
--Here's where the aggregation and ordering happen
collect(sometype(SomeValue, SomeOtherValue)
order by SomeOrderingValue)
as someTypes
)
) result
from
(
--Test data: note the unordered SoemOrderingValue.
select 1 someId, 3 SomeOrderingValue, '3' SomeValue, '3' SomeOtherValue
from dual union all
select 1 someId, 1 SomeOrderingValue, '1' SomeValue, '1' SomeOtherValue
from dual union all
select 1 someId, 2 SomeOrderingValue, '2' SomeValue, '2' SomeOtherValue
from dual
) foo
group by someId;
--Here are the results, aggregated and ordered.
SOMEID RESULT
------ ------
1 1+1,2+2,3+3
Oracle is very likely be rewriting your query and getting rid of the subquery. I've never done anything like what you're doing, but could you add the NO_UNNEST hint on the inner query?
SELECT SomeId, myAggregationFunction(Item) FROM
(
SELECT /*+ NO_UNNEST */
Foo.SomeId, ...
Even then, I'm really not sure what it will do with an ORDER BY inside a subquery.
I am developing an application in Oracle APEX. I have a string with user id's that is comma deliminated which looks like this,
45,4932,20,19
This string is stored as
:P5_USER_ID_LIST
I want a query that will find all users that are within this list my query looks like this
SELECT * FROM users u WHERE u.user_id IN (:P5_USER_ID_LIST);
I keep getting an Oracle error: Invalid number. If I however hard code the string into the query it works. Like this:
SELECT * FROM users u WHERE u.user_id IN (45,4932,20,19);
Anyone know why this might be an issue?
A bind variable binds a value, in this case the string '45,4932,20,19'. You could use dynamic SQL and concatenation as suggested by Randy, but you would need to be very careful that the user is not able to modify this value, otherwise you have a SQL Injection issue.
A safer route would be to put the IDs into an Apex collection in a PL/SQL process:
declare
array apex_application_global.vc_arr2;
begin
array := apex_util.string_to_table (:P5_USER_ID_LIST, ',');
apex_collection.create_or_truncate_collection ('P5_ID_COLL');
apex_collection.add_members ('P5_ID_COLL', array);
end;
Then change your query to:
SELECT * FROM users u WHERE u.user_id IN
(SELECT c001 FROM apex_collections
WHERE collection_name = 'P5_ID_COLL')
An easier solution is to use instr:
SELECT * FROM users u
WHERE instr(',' || :P5_USER_ID_LIST ||',' ,',' || u.user_id|| ',', 1) !=0;
tricks:
',' || :P5_USER_ID_LIST ||','
to make your string ,45,4932,20,19,
',' || u.user_id|| ','
to have i.e. ,32, and avoid to select the 32 being in ,4932,
I have faced this situation several times and here is what i've used:
SELECT *
FROM users u
WHERE ','||to_char(:P5_USER_ID_LIST)||',' like '%,'||to_char(u.user_id)||',%'
ive used the like operator but you must be a little carefull of one aspect here: your item P5_USER_ID_LIST must be ",45,4932,20,19," so that like will compare with an exact number "',45,'".
When using it like this, the select will not mistake lets say : 5 with 15, 155, 55.
Try it out and let me know how it goes;)
Cheers ,
Alex
Create a native query rather than using "createQuery/createNamedQuery"
The reason this is an issue is that you cannot just bind an in list the way you want, and just about everyone makes this mistake at least once as they are learning Oracle (and probably SQL!).
When you bind the string '32,64,128', it effectively becomes a query like:
select ...
from t
where t.c1 in ('32,64,128')
To Oracle this is totally different to:
select ...
from t
where t.c1 in (32,64,128)
The first example has a single string value in the in list and the second has a 3 numbers in the in list. The reason you get an invalid number error is because Oracle attempts to cast the string '32,64,128' into a number, which it cannot do due to the commas in the string.
A variation of this "how do I bind an in list" question has come up on here quite a few times recently.
Generically, and without resorting to any PLSQL, worrying about SQL Injection or not binding the query correctly, you can use this trick:
with bound_inlist
as
(
select
substr(txt,
instr (txt, ',', 1, level ) + 1,
instr (txt, ',', 1, level+1) - instr (txt, ',', 1, level) -1 )
as token
from (select ','||:txt||',' txt from dual)
connect by level <= length(:txt)-length(replace(:txt,',',''))+1
)
select *
from bound_inlist a, users u
where a.token = u.id;
If possible the best idea may be to not store your user ids in csv! Put them in a table or failing that an array etc. You cannot bind a csv field as a number.
Please dont use: WHERE ','||to_char(:P5_USER_ID_LIST)||',' like '%,'||to_char(u.user_id)||',%' because you'll force a full table scan although with the users table you may not have that many so the impact will be low but against other tables in an enterprise environment this is a problem.
EDIT: I have put together a script to demonstrate the differences between the regex method and the wildcard like method. Not only is regex faster but it's also a lot more robust.
-- Create table
create table CSV_TEST
(
NUM NUMBER not null,
STR VARCHAR2(20)
);
create sequence csv_test_seq;
begin
for j in 1..10 loop
for i in 1..500000 loop
insert into csv_test( num, str ) values ( csv_test_seq.nextval, to_char( csv_test_seq.nextval ));
end loop;
commit;
end loop;
end;
/
-- Create/Recreate primary, unique and foreign key constraints
alter table CSV_TEST
add constraint CSV_TEST_PK primary key (NUM)
using index ;
alter table CSV_TEST
add constraint CSV_TEST_FK unique (STR)
using index;
select sysdate from dual;
select *
from csv_test t
where t.num in ( Select Regexp_Substr('100001, 100002, 100003 , 100004, 100005','[^,]+', 1, Level) From Dual
Connect By Regexp_Substr('100001, 100002,100003, 100004, 100005', '[^,]+', 1, Level) Is Not Null);
select sysdate from dual;
select *
from csv_test t
where ('%,' || '100001,100002, 100003, 100004 ,100005' || ',%') like '%,' || num || ',%';
select sysdate from dual;
select *
from csv_test t
where t.num in ( Select Regexp_Substr('100001, 100002, 100003 , 100004, 100005','[^,]+', 1, Level) From Dual
Connect By Regexp_Substr('100001, 100002,100003, 100004, 100005', '[^,]+', 1, Level) Is Not Null);
select sysdate from dual;
select *
from csv_test t
where ('%,' || '100001,100002, 100003, 100004 ,100005' || ',%') like '%,' || num || ',%';
select sysdate from dual;
drop table csv_test;
drop sequence csv_test_seq;
Solution from Tony Andrews works for me. The process should be added to "Page processing" >> "After submit">> "Processes".
As you are Storing User Ids as String so You can Easily match String Using Like as Below
SELECT * FROM users u WHERE u.user_id LIKE '%'||(:P5_USER_ID_LIST)||'%'
For Example
:P5_USER_ID_LIST = 45,4932,20,19
Your Query Surely Will return Any of 1 User Id which Matches to Users table
This Will Surely Resolve Your Issue , Enjoy
you will need to run this as dynamic SQL.
create the entire string, then run it dynamically.