In ORACLE please.
Is it possible to have a variable in the 'ORDER BY' Statment?
So iam currenty creating a procedure in which I need to have a dynamic Order by.
Is there any way to do this ?
CREATE OR REPLACE PROCEDURE TEST1
vorder varchar(250);
...
vOrder := 'number';
FOR o IN (SELECT * FROM TABLENAME order by vOrder)
LOOP
-- Some stuff ---
END LOPP;
....
The only way to really have a dynamic order by clause instead of just having a list of predefined options as suggested by Alex, would be to use a dynamic sql cursor.
TYPE curType IS REF CURSOR;
vCur curType;
vRec tablename%ROWTYPE;
vOrd VARCHAR2(250) := 'column';
BEGIN
OPEN vCur FOR 'SELECT * FROM tablename ORDER BY '||vOrd';
LOOP
FETCH vCur INTO vRec;
EXIT WHEN cur%NOTFOUND;
END LOOP;
CLOSE vCur;
END;
/
Related
I have a table TestTable with columns of col_test1, col_test2, col_test3 ...
and I want to create a loop that accesses each of these columns individually and find the max value and place it in the variable made in the declare block and simply dbms.out.put it.
Declare
my_array sys.dbms_debug_vc2coll := sys.dbms_debug_vc2coll('col_test1','col_test2','col_test2');
v_test number(8,0);
Begin
for r in my_array.first..my_array.last
loop
select max(my_array(r)) into v_test from TestTable;
dbms_output.put_line(v_test);
end loop;
End;
/
The output I get is just the string 'col_test1'which should be 50.
This is done through oracle SQL. Is there any way to achieve this?
You could use dynamic SQL for this
Declare
my_array sys.dbms_debug_vc2coll := sys.dbms_debug_vc2coll('col_test1','col_test2','col_test2');
v_test number(8,0);
Begin
for r in my_array.first..my_array.last
loop
execute immediate 'select max(' || my_array(r) || ') from TestTable'
into v_test;
dbms_output.put_line(v_test);
end loop;
End;
If you're going to resort to dynamic SQL, however, it would generally make more sense to build a single SQL statement that took that max of all three columns in one pass rather than potentially doing three separate table scans on the same table.
I am building a procedure, where I`m first creating a select statement and store it in an VARCAHR variable.
I now want to execute that query and store the whole result set in an variable to loop through it or use directly in a for loop.
I only find examples where the Select is hard written in the for loop definition.
How do i exchange the Select statement with my variable that holds my select statement?
for r IN (SELECT ... FROM ...)
loop
--do sth;
end loop;
how i want to use it :
statement := 'SELECT .... FROM ...';
for r IN (statement) -- HOW TO DO THIS
loop
--do sth;
end loop;
For a dynamic ref cursor, you need to define everything explicitly:
declare
sqlstring long := 'select 123 as id, ''demo'' as somevalue from dual where dummy = :b1';
resultset sys_refcursor;
type demo_rectype is record
( id integer
, somevalue varchar2(30) );
demorec demo_rectype;
begin
open resultset for sqlstring using 'X';
loop
fetch resultset into demorec;
exit when resultset%notfound;
dbms_output.put_line('id=' || demorec.id || ' somevalue=' || demorec.somevalue);
end loop;
close resultset;
end;
You can parse the cursor and figure out the column names and datatypes with DBMS_SQL. Example here: www.williamrobertson.net/documents/refcursor-to-csv.shtml
There is a table contains this kind of data: select to_char(sysdate,'day') from dual in a column. I want to get results of the every query that the table keeps.
My result set should be the result of select to_char(sysdate,'day') from dual query. So in this case it is a tuesday.
SO_SQL_BODY is Varchar2.
I wrote this code but it returns only table data.
CREATE or replace PROCEDURE a_proc
AS
CURSOR var_cur IS
select SO_SQL_BODY FROM SO_SUB_VARS group by SO_SQL_BODY;
var_t var_cur%ROWTYPE;
TYPE var_ntt IS TABLE OF var_t%TYPE;
var_names var_ntt;
BEGIN
OPEN var_cur;
FETCH var_cur BULK COLLECT INTO var_names;
CLOSE var_cur;
FOR indx IN 1..var_names.COUNT LOOP
DBMS_OUTPUT.PUT_LINE(var_names(indx).SO_SQL_BODY);
END LOOP;
END a_proc;
DECLARE
res varchar2(4000);
sql_str varchar2(1000);
BEGIN
FOR r IN
(select SO_SQL_BODY FROM SO_SUB_VARS WHERE SO_SQL_BODY IS NOT NULL
)
LOOP
sql_str := r.SO_SQL_BODY;
EXECUTE immediate sql_str INTO res;
dbms_output.put_line(sql_str);
dbms_output.put_line('***********************');
dbms_output.put_line(res);
dbms_output.put_line('***********************');
END LOOP;
END;
/
Try this - iterate to not null records - execute them and print the result.This script works supposing the fact that SO_SQL_BODY contains a query which projects only one column.Also if the projection is with more than two columns then try to use a refcursor and dbms_sql package
İf var_names(indx).SO_SQL_BODY output is a runnable sql text;
CREATE or replace PROCEDURE a_proc
AS
CURSOR var_cur IS
select SO_SQL_BODY FROM SO_SUB_VARS group by SO_SQL_BODY;
var_t var_cur%ROWTYPE;
TYPE var_ntt IS TABLE OF var_t%TYPE;
var_names var_ntt;
BEGIN
OPEN var_cur;
FETCH var_cur BULK COLLECT INTO var_names;
CLOSE var_cur;
FOR indx IN 1..var_names.COUNT LOOP
DBMS_OUTPUT.PUT_LINE(var_names(indx).SO_SQL_BODY);
EXECUTE IMMEDIATE var_names(indx).SO_SQL_BODY;
END LOOP;
END a_proc;
You don't need a full cursor for this example. An implicit one would make it a lot shorter.
create or replace procedure a_proc is
lReturnValue varchar2(250);
begin
for q in (select so_sql_body from so_sub_vars group by so_sql_body)
loop
execute immediate q.so_sql_body into lReturnValue;
dbms_output.put_line(lReturnValue);
end loop;
end a_proc;
You should add an exception handler that will care for cases where there is a bad SQL query in your table. Also note that executing querys saved in a database table is your entry point to SQL injection.
I have one question about "EXECUTE IMMEDIATE".
I have dynamicly changed table name in next plsql statement
DECLARE
TYPE CurTyp IS REF CURSOR;
cur CurTyp;
str1 VARCHAR2(30);
str2 VARCHAR2(30);
table_name VARCHAR2(30);
BEGIN
select data
into table_name
from ref
where o_id = 111
and a_id = 222;
OPEN cur FOR
'select name, sname from :1 b,myobjects a where a.obj_id = b.obj_id'
USING table_name;
LOOP
FETCH cur INTO str1, str2;
EXIT WHEN cur%NOTFOUND;
dbms_output.put_line(str1||str2);
END LOOP;
CLOSE cur;
END
Is it possible to read the result of next Execute Immediate query to cursor?
'select name, sname from :1 b,myobjects a where a.obj_id = b.obj_id'
USING table_name;
Or maybe is there any way to do this?
Thanks in advance.
For object names you must use concatenation, not bind variables.
From the Dynamic SQL chapter of the PL/SQL Language Reference:
The database uses the values of bind variables exclusively and does
not interpret their contents in any way.
Bind variables help with security and performance. But they won't work with objects like tables. If you pass in a table name then Oracle must interpret the contents, which will negate the security and performance benefits.
You can use ref_cursor
see http://docs.oracle.com/cd/B10500_01/appdev.920/a96590/adg09dyn.htm
the example:
CREATE OR REPLACE PROCEDURE query_invoice(
month VARCHAR2,
year VARCHAR2) IS
TYPE cur_typ IS REF CURSOR;
c cur_typ;
query_str VARCHAR2(200);
inv_num NUMBER;
inv_cust VARCHAR2(20);
inv_amt NUMBER;
BEGIN
query_str := 'SELECT num, cust, amt FROM inv_' || month ||'_'|| year
|| ' WHERE invnum = :id';
OPEN c FOR query_str USING inv_num;
LOOP
FETCH c INTO inv_num, inv_cust, inv_amt;
EXIT WHEN c%NOTFOUND;
-- process row here
END LOOP;
CLOSE c;
END;
/
but as #jonearles said, you can't insert the table names as params
My dynamic sql below to alter a table & create columns based on the output of a query is giving error.
Query :
DECLARE
CURSOR c1 is select distinct WP_NO from temp;
cnum VARCHAR2(255);
BEGIN
FOR cnum in c1
LOOP
EXECUTE IMMEDIATE 'Alter table temp_col add (:1 varchar2(255))' using cnum;
END LOOP;
COMMIT;
END;
Error :
PLS-00457: expressions have to be of SQL types
This is happening because bind variables are not allowed in DDL statements.
Consider trying it without using the bind variable:
DECLARE
CURSOR c1 is select distinct WP_NO from temp;
cnum VARCHAR2(255);
BEGIN
FOR cnum in c1
LOOP
EXECUTE IMMEDIATE 'Alter table temp_col add ('|| cnum ||' varchar2(255))';
END LOOP;
COMMIT;
END;
You have a conflict with the cnum symbol, which you use both as a local variable and for the current row of the cursor.
You probably want this:
DECLARE
CURSOR c1 is select distinct WP_NO from temp;
BEGIN
FOR current_row in c1
LOOP
EXECUTE IMMEDIATE 'Alter table temp_col add (:1 varchar2(255))' using current_row.WP_NO;
END LOOP;
COMMIT;
END;
As you can see, you don't need to declare the current_row variable that you use in the for loop.