I have a function that returns a SYS_REFCURSOR that has a single row but multiple columns. What I'm looking to do is to be able to have a SQL query that has nested sub-queries using the column values returned in the SYS_REFCURSOR. Alternative ideas such as types, etc would be appreciated. Code below is me writing on-the-fly and hasn't been validated for syntax.
--Oracle function
CREATE DummyFunction(dummyValue AS NUMBER) RETURN SYS_REFCURSOR
IS
RETURN_DATA SYS_REFCURSOR;
BEGIN
OPEN RETURN_DATA
SELECT
TO_CHAR(dummyValue) || 'A' AS ColumnA
,TO_CHAR(dummyValue) || 'B' AS ColumnB
FROM
DUAL;
RETURN RETURN_DATA;
END;
--sample query with sub-queries; does not work
SELECT
SELECT ColumnA FROM DummyFunction(1) FROM DUAL AS ColumnA
,SELECT ColumnB FROM DummyFunction(1) FROM DUAL AS ColumnB
FROM
DUAL;
A SYS_REFCURSOR won't work for the intended use - you need to create an Oracle TYPE:
CREATE TYPE your_type IS OBJECT (
ColumnA VARCHAR2(100),
ColumnB VARCHAR2(100)
)
Update your function:
CREATE DummyFunction(dummyValue AS NUMBER)
RETURN your_type
IS
BEGIN
INSERT INTO your_type
SELECT TO_CHAR(dummyValue) || 'A' AS ColumnA,
TO_CHAR(dummyValue) || 'B' AS ColumnB
FROM DUAL;
RETURN your_type;
END;
Then you can use:
SELECT (SELECT ColumnA FROM table(DummyFunction(1))) AS ColumnA,
(SELECT ColumnB FROM table(DummyFunction(1))) AS ColumnB
FROM DUAL
The example is overcomplicated - all you need to use is:
SELECT x.columna,
x.columnb
FROM table(DummyFunction(1)) x
Related
I have a table "test_calculate" this has a column "CONN_BY" having values
column can have more than 2 number to multiply and this table may contain millions of rows , I need to get the result of the calculation from "CONN_BY" to "MVP".
I have used xmlquery for the calculation and dynamic query but these are quite slow. Is there another way which is much faster .Please suggest.
You can try the dynamic query.
Create a function which returns the calculated value and use it in your insert or select queries.
CREATE OR REPLACE FUNCTION UFN_CALCULATE (CLM_VALUE VARCHAR2)
RETURN NUMBER IS
RES_VAL NUMBER;
BEGIN
EXECUTE IMMEDIATE 'select '||CLM_VALUE||' FROM DUAL' INTO RES_VAL;
RETURN RES_VAL;
END;
You can use that function like below.
SELECT UFN_CALCULATE('.0876543 * .09876') FROM DUAL;
SELECT UFN_CALCULATE(CONN_BY) FROM YOUR_TABLE;
One option is using select ... connect by level <= regexp_count(conn_by,'[^*]+')... query for the implicit cursor within a PL/SQL code block
SQL> set serveroutput on
SQL> declare
mvp owa.nc_arr; -- numeric array to initialize each multiplication to 1 for each id value
begin
dbms_output.put_line('ID MVP');
dbms_output.put_line('--------');
for c in
(
select id,
to_number( regexp_substr(conn_by,'[^*]+',1,level) ) as nr,
level as lvl , max( level ) over ( partition by id ) as mx_lvl
from test_calculate
connect by level <= regexp_count(conn_by,'[^*]+')
and prior sys_guid() is not null
and prior conn_by = conn_by
order by id, lvl
)
loop
if c.lvl = 1 then mvp(c.id) := 1; end if;
mvp(c.id) := c.nr * mvp(c.id);
if c.lvl = c.mx_lvl then
dbms_output.put_line(c.id||' '||mvp(c.id));
end if;
end loop;
end;
/
where test_calculate is assumed to have an identity column(id)
Demo
I'am trying UNION ALL many tables into a new table.The columns of the old tables are the same, but the order of the columns is different, so the below SQL statement will get wrong result:
CREATE TABLE sum_7_2018_xia_weijian
AS
(
SELECT * FROM huiwen
UNION
SELECT * FROM penglai
UNION
SELECT * FROM baoluo
UNION
SELECT * FROM dongge
UNION
SELECT * FROM resultdonglu
UNION
SELECT * FROM resultwencheng
UNION
SELECT * FROM tan_illeg
);
I finally corrected it, but the SQL statements is too redundant:
step 1. get column names of one of the old tables named huiwen
SELECT string_agg(column_name, ',')
FROM information_schema.columns
WHERE table_schema = 'public' AND table_name = 'huiwen';
results:
> string_agg
> ----------------------------------------------------------------------
>
> gid,id,geom,sxm,sxdm,sxxzqdm,xzqhdm,xzmc,sfzgjsyd,sfkfbj,sfjbnt,sfld,sflyhx,sfhyhx
step 2. union tables as a new table. I copy the string_agg of table huiwen to each SELECT-UNION to keep the order of columns, this is clumsy.
CREATE TABLE sum_2018_xia_weijian
AS
(
SELECT gid,id,geom,sxm,sxdm,sxxzqdm,xzqhdm,xzmc,sfzgjsyd,sfkfbj,sfjbnt,sfld,sflyhx,sfhyhx
FROM huiwen
UNION ALL
SELECT gid,id,geom,sxm,sxdm,sxxzqdm,xzqhdm,xzmc,sfzgjsyd,sfkfbj,sfjbnt,sfld,sflyhx,sfhyhx
FROM penglai
UNION ALL
SELECT gid,id,geom,sxm,sxdm,sxxzqdm,xzqhdm,xzmc,sfzgjsyd,sfkfbj,sfjbnt,sfld,sflyhx,sfhyhx
FROM baoluo
);
results:
> Query returned successfully: 2206 rows affected, 133 msec execution time.
I tried to do some optimization by pl/pgSQL using Declarations of variable to handle column names, but failed to find any SQL data type can handle this. Using of RECORD result Pseudo-Types ERROR：
CREATE or replace FUNCTION ct() RETURNS RECORD AS $$
DECLARE
clms RECORD;
BEGIN
SELECT column_name INTO clms
FROM information_schema.columns
WHERE table_schema = 'public' AND table_name = 'huiwen';
RETURN clms;
END;
$$ LANGUAGE plpgsql;
CREATE TABLE sum_2018_xia_weijian
AS
(
SELECT ct() FROM huiwen
UNION ALL
SELECT ct() FROM penglai
UNION ALL
SELECT ct() FROM baoluo
UNION ALL
SELECT ct() FROM dongge
UNION ALL
SELECT ct() FROM resultdonglu
UNION ALL
SELECT ct() FROM resultwencheng
UNION ALL
SELECT ct() FROM tan_illeg
);
You may use STRING_AGG twice for getting the UNION ALL. You can get all the columns in specific order by explicitly ordering it by column_name in the string_agg.
Here's a generic function which takes an array of tables and a final table name.
CREATE or replace FUNCTION fn_create_tab(tname_arr TEXT[], p_tab_name TEXT)
RETURNS VOID AS $$
DECLARE
l_select TEXT;
BEGIN
select STRING_AGG(query,' UNION ALL ' ) INTO l_select
FROM
(
SELECT 'select ' || string_agg( column_name,','
ORDER BY column_name ) || ' from ' || table_name as query
FROM information_schema.columns
WHERE table_schema = 'public' AND table_name = ANY (tname_arr)
GROUP BY table_name
) s;
IF l_select IS NOT NULL
THEN
EXECUTE format ('DROP TABLE IF EXISTS %I',p_tab_name);
EXECUTE format ('create table %I AS %s',p_tab_name,l_select);
END IF;
END;
$$ LANGUAGE plpgsql;
Now, run the function like this:
select fn_create_tab(ARRAY['huiwen','penglai'],'sum_2018_xia_weijian');
Instead of making the programming block complex you can follow some below concepts from the documentation of Union or Union All as it says :
The number of columns in all queries must be the same.
The corresponding columns must have the compatible data type.
The column names of the first query determine the column names of the combined result set.
The GROUP BY and HAVING clauses are applied to each individual query, not the final result set.
The ORDER BY clause is applied to the combined result set, not within the individual result set.
By following the 3rd point make your Union query adjusted to refer to the table whose column order is expected in the result.
I have a table (let's name it source_tab) where I store list of all database tables that meet some criteria.
tab_name: description:
table1 some_desc1
table2 some_desc2
Now I need to execute a select statement on each of these tables and return a result as a table (I created custom TYPE). However I have a problem - when using bulk collect, only the last select statement is returned. The same issue was with open cursor. Is there any possibility to achieve this goal, another then concatenating all select statements using union all and executing it as one statement? And because I'm the begginer in sql, my second question is, is it ok to use this dynamic sql in terms of sql injection issues? Below is simplified version of my code:
CREATE OR REPLACE FUNCTION my_function RETURN newly_created_table_type IS
ret_tab_type newly_created_table_type;
BEGIN
for r in (select * from source_tab)
loop
execute immediate 'select value1, value2,''' || r.tab_name || ''' from ' || r.tab_name bulk collect into ret_tab_type;
end loop;
return ret_tab_type;
END;
I'm using Oracle 11.
In your case you are trying to populate a collection dynamically and wanted result in a single collection. In your case its not possible to do that in a single loop. Also as mentioned by #OldProgrammer, piperow would be a better solution from performance point. See below demo:
--Tables and Values:
CREATE TABLE SOURCE_TAB(TAB_NAME VARCHAR2(100), DESCRIPTION VARCHAR2(100));
/
SELECT * FROM SOURCE_TAB;
/
INSERT INTO SOURCE_TAB VALUES('table1','some_desc1');
INSERT INTO SOURCE_TAB VALUES('table2','some_desc2');
/
CREATE TABLE TABLE1(COL1 NUMBER, COL2 NUMBER);
/
INSERT INTO TABLE1 VALUES(1,2);
INSERT INTO TABLE1 VALUES(3,4);
INSERT INTO TABLE1 VALUES(5,6);
/
Select * from TABLE1;
/
CREATE TABLE TABLE2(COL1 NUMBER, COL2 NUMBER);
/
INSERT INTO TABLE2 VALUES(7,8);
INSERT INTO TABLE2 VALUES(9,10);
INSERT INTO TABLE2 VALUES(11,12);
/
Select * from TABLE2;
/
--Object Created
--UDT
CREATE OR REPLACE TYPE NEWLY_CREATED_TABLE_TYPE IS OBJECT (
VALUE1 NUMBER,
VALUE2 NUMBER
);
/
--Type of UDT
CREATE OR TYPE NEWLY_CRTD_TYP AS TABLE OF NEWLY_CREATED_TABLE_TYPE;
/
--Function:
--Function
CREATE OR REPLACE FUNCTION MY_FUNCTION
RETURN NEWLY_CRTD_TYP PIPELINED
AS
CURSOR CUR_TAB
IS
SELECT *
FROM SOURCE_TAB;
RET_TAB_TYPE NEWLY_CRTD_TYP;
BEGIN
FOR I IN CUR_TAB
LOOP
--Here i made sure that all the tables have col1 & col2 columns since you are using dynamic sql.
EXECUTE IMMEDIATE 'select NEWLY_CREATED_TABLE_TYPE(COL1, COL2) from '|| I.TAB_NAME
BULK COLLECT INTO RET_TAB_TYPE;
EXIT WHEN CUR_TAB%NOTFOUND;
FOR REC IN 1 .. RET_TAB_TYPE.COUNT
LOOP
PIPE ROW (RET_TAB_TYPE (REC) );
END LOOP;
END LOOP;
RETURN;
END;
/
Output:
SQL> Select * from table(MY_FUNCTION);
VALUE1 VALUE2
---------- ----------
1 2
3 4
5 6
7 8
9 10
11 12
6 rows selected.
May be you can combine all the queries into one using UNION ALL before execution, if the number and type of columns to be retrieved from all the tables are identical.
CREATE OR REPLACE FUNCTION my_function
RETURN newly_created_table_type
IS
ret_tab_type newly_created_table_type;
v_query VARCHAR2 (4000);
BEGIN
SELECT LISTAGG (' select VALUE1,VALUE2 FROM ' || tab_name, ' UNION ALL ')
WITHIN GROUP (ORDER BY tab_name)
INTO v_query
FROM source_tab;
EXECUTE IMMEDIATE v_query BULK COLLECT INTO ret_tab_type;
RETURN ret_tab_type;
END;
You could then use a single select statement to get all the values.
select * FROM TABLE ( my_function );
I am trying to return a table via a function in an Oracle package:
CREATE OR REPLACE PACKAGE test AS
TYPE rec IS RECORD(
col1 VARCHAR(10));
TYPE rec_table IS TABLE OF rec;
FUNCTION get_table(input VARCHAR2)
RETURN rec_table
PIPELINED;
END;
CREATE OR REPLACE PACKAGE BODY test AS
FUNCTION get_table(input VARCHAR2)
RETURN rec_table
PIPELINED IS
rec1 rec;
BEGIN
SELECT * INTO rec1
FROM
(
SELECT '1' from dual
UNION ALL
SELECT '2' from dual
);
PIPE ROW (rec1)
RETURN;
END get_table;
END;
but when I try to run
select * from table(test.get_table('blah'))
I get an error: exact fetch returns more then requested number of rows
I've read a bit about BULK COLLECT INTO, but I am not understanding the syntax...
The following piece of code:
SELECT '1' from dual
UNION ALL
SELECT '2' from dual
Returns two, not one record, and you are trying to put those two records in one rec variable. You should instead loop through the results of the UNION:
FOR v_rec IN (
SELECT *
FROM (
SELECT '1' from dual
UNION ALL
SELECT '2' from dual
)
)
LOOP
PIPE ROW (v_rec);
END LOOP;
I'm trying to return a multiple values in a %rowtype from a function using two table(employees and departments), but it not working for me.
create or replace function get_employee
(loc in number)
return mv_emp%rowtype
as
emp_record mv_emp%rowtype;
begin
select a.first_name, a.last_name, b.department_name into emp_record
from employees a, departments b
where a.department_id=b.department_id and location_id=loc;
return(emp_record);
end;
The above function compiled without any error? What is the type of MV_EMP? Ideally, it should be something like below.
create or replace type emp_type
(
first_name varchar2(20)
, last_name varchar2(20)
, depart_name varchar2(20)
)
/
create or replace function get_employee
(loc in number)
return emp_type
as
emp_record emp_type;
begin
select a.first_name, a.last_name, b.department_name into emp_record
from employees a, departments b
where a.department_id=b.department_id and location_id=loc;
return(emp_record);
end;
create type t_row as object (a varchar2(10));
create type t_row_tab as table of t_row;
We will now create a function which will split the input string.
create or replace function get_number(pv_no_list in varchar2) return t_row_tab is
lv_no_list t_row_tab := t_row_tab();
begin
for i in (SELECT distinct REGEXP_SUBSTR(pv_no_list, '[^,]+', 1, LEVEL) no_list FROM dual
CONNECT BY REGEXP_SUBSTR(pv_no_list, '[^,]+', 1, LEVEL) IS NOT NULL)
loop
lv_no_list.extend;
lv_no_list(lv_no_list.last) := t_row(i.no_list);
end loop;
return lv_no_list;
end get_number;
Once the function is in place we can use the table clause of sql statement to get the desired result. As desired we got multiple values returned from the function.
SQL> select * from table(get_number('1,2,3,4'));
A
----------
1
3
2
4
So now our function is simply behaving like a table. There can be a situation where you want these comma separated values to be a part of "IN" clause.
For example :
select * from dummy_table where dummy_column in ('1,2,3,4');
But the above query will not work as '1,2,3,4' is a string and not individual numbers. To solve this problem you can simply use following query.
select * from dummy_table where dummy_column in ( select * from table(get_number('1,2,3,4')) );
References : http://www.oraclebin.com/2012/12/returning-multiple-values-from-function.html
CREATE OR replace FUNCTION Funmultiple(deptno_in IN NUMBER)
RETURN NUMBER AS v_refcursur SYS_REFCURSOR;
BEGIN
OPEN v_refcursor FOR
SELECT *
FROM emp
WHERE deptno = deptno_in;
retun v_refcursor;
END;
To call it, use:
variable x number
exec :x := FunMultiple(10);
print x