The following Oracle SQL code generates the error "ORA-02287: sequence number not allowed here":
INSERT INTO Customer (CustomerID,Name) VALUES (Customer_Seq.nextval,'AAA');
SELECT * FROM Customer where CustomerID=Customer_Seq.currval;
The error occurs on the second line (SELECT statement). I don't really understand the problem, because this does work:
INSERT INTO Customer (CustomerID,Name) VALUES (Customer_Seq.nextval,'AAA');
SELECT Customer_Seq.currval from dual;
You have posted some sample code, so it is not clear what you are trying to achieve. If you want to know the assigned value, say for passing to some other procedure you could do something like this:
SQL> var dno number
SQL> insert into dept (deptno, dname, loc)
2 values (deptno_seq.nextval, 'IT', 'LONDON')
3 returning deptno into :dno
4 /
1 row created.
SQL> select * from dept
2 where deptno = :dno
3 /
DEPTNO DNAME LOC
---------- -------------- -------------
55 IT LONDON
SQL>
Edit
We can use the RETURNING clause to get the values of any column, including those which have been set with default values or by trigger code.
You don't say what version of Oracle you are using. There have in the past been limitations on where sequences can be used in PL/SQL - mostly if not all gone in 11G. Also, there are restrictions in SQL - see this list.
In this case you may need to write:
SELECT Customer_Seq.currval INTO v_id FROM DUAL;
SELECT * FROM Customer where CustomerID=v_id;
(Edited after comments).
This doesn't really directly answer your question, but maybe what you want to do can be resolved using a the INSERT's RETURNING clause?
DECLARE
-- ...
last_rowid rowid;
-- ...
BEGIN
-- ...
INSERT INTO Customer (CustomerID,Name) VALUES (Customer_Seq.nextval,'AAA') RETURNING rowid INTO last_rowid;
SELECT * FROM Customer where rowid = last_rowid;
-- ...
END;
/
You may not use a sequence in a WHERE clause - it does look natural in your context, but Oracle does not allow the reference in a comparison expression.
[Edit]
This would be a PL/SQL implementation:
declare
v_custID number;
cursor custCur is
select customerid, name from customer
where customerid = v_custID;
begin
select customer_seq.nextval into v_custID from dual;
insert into customer (customerid, name) values (v_custID, 'AAA');
commit;
for custRow in custCur loop
dbms_output.put_line(custRow.customerID||' '|| custRow.name);
end loop;
end;
You have not created any
sequence
First create any sequence its cycle and cache. This is some basic example
Create Sequence seqtest1
Start With 0 -- This Is Hirarchy Starts With 0
Increment by 1 --Increments by 1
Minvalue 0 --With Minimum value 0
Maxvalue 5 --Maximum Value 5. So The Cycle Of Creation Is Between 0-5
Nocycle -- No Cycle Means After 0-5 the Insertion Stopes
Nocache --The cache Option Specifies How Many Sequence Values Will Be Stored In Memory For Faster Access
You cannot do Where Clause on Sequence in SQL beacuse you cannot filter a sequence . Use procedures like #APC said
Related
I have procedure like this...
declare
v_psg varchar2(10);
id_no number;
begin
select value into v_psg from settings_am where key = 'PSG';
select id into id_no from product where to_char(psg) in (v_psg);
end;`
The value returned from select value into v_psg from settings_am where key = 'PSG'; would be
'1','2','3'
when i run this procedure i am returned with ora error - ORA-01403.
please advise how i should pass the v_psg value to psg column of product table?
EDIT - Tried with test case suggested
If you got ORA-01403, you were kind of lucky. It is the NO_DATA_FOUND error, which means that one (probably the first) query didn't return anything.
Those two statements could be combined into
select id
from product
where to_char(psg) in (select value
from settings_am
where key = 'PSG'
);
Why would you select value first, and then use it in another query? Besides, it just wouldn't work. v_psg is declared as VARCHAR2 variable. The way you described it, it contains the following string: '1','2','3', as if this is what you have:
SQL> create table settings_am (key varchar2(10),
2 value varchar2(20)); --> note size here
Table created.
SQL> insert into settings_am (key, value)
2 values ('PSG', q'['1','2','3']');
1 row created.
SQL> select * From settings_am;
KEY VALUE
---------- --------------------
PSG '1','2','3'
SQL>
As you can see, I enlarged the value column size, although variable you declared says 10. Why? Because of
SQL> select length(value) from settings_am where key = 'PSG';
LENGTH(VALUE)
-------------
11
i.e. you can't put something that is long 11 into something that accepts length 10.
Or, if your data actually contains 3 rows for the PSG key, are those values already enclosed into single quotes? If so, that's strange; people usually don't do that. Anyway, suppose that you managed to get string '1,2,3' (which is what I presume you actually have) into a VARCHAR2 variable, then you have to split it into rows in order to be able to use it in the IN clause:
SQL> create table product (id number, psg varchar2(10));
Table created.
SQL> insert into product (id, psg) values (100, '1');
1 row created.
SQL> insert into product (id, psg) values (200, '2');
1 row created.
SQL>
Query is then (where lines #3 - 5 represent splitting a string into rows):
SQL> select p.id
2 from product p
3 where p.psg in (select regexp_substr('&&v_psg', '[^,]+', 1, level)
4 from dual
5 connect by level <= regexp_count('&&v_psg', ',') + 1
6 );
Enter value for v_psg: 1,2,3
ID
----------
100
200
So, wouldn't it be simpler to use
SQL> select id
2 from product
3 where to_char(psg) in (select value
4 from settings_am
5 where key = 'PSG'
6 );
ID
----------
100
200
SQL>
Note that both options also show why your query is wrong: you can't put two values (rows) into a variable declared as id_no number; as you'd get TOO_MANY_ROWS error.
Finally, what is it that you'd want to do? What problem are you trying to solve? Apparently, except for special cases (only one row for each value) your query can't work. If you could provide test case (create table & insert into sample data), as well as expected output, it would be easier to help you.
I have a workplace problem to which I am looking for an easy solution.
I am trying to replicate it in a smaller scenario.
Problem in short
I want to use nvl inside an in clause. Currently I have an input string which consists of a name. It is used in a where clause like below
and column_n = nvl(in_parameter,column_n)
Now I want to pass multiple comma separated values in same input parameter. So if I replace = with in, and transpose the input comma separated string as rows, I cannot use the nvl clause with it.
Problem in Detail
Lets consider an Employee table emp1.
Emp1
+-------+-------+
| empno | ename |
+-------+-------+
| 7839 | KING |
| 7698 | BLAKE |
| 7782 | CLARK |
+-------+-------+
Now this is a simple version of an existing stored procedure
create or replace procedure emp_poc(in_names IN varchar2)
as
cnt integer;
begin
select count(*)
into cnt
from emp1
where
ename = nvl(in_names,ename); --This is one of the condition where we will make the change.
dbms_output.put_line(cnt);
end;
So this will give the count of number of employees passed as Input Parameter. But if we pass null, it will return the whole count of employee becuase of the nvl.
So these procedure calls will render the given outputs.
Procedure Call Output
exec emp_poc('KING') 1
exec emp_poc('JOHN') 0
exec emp_poc(null) 3
Now what I want to achieve is to add another functionality. So exec emp_poc('KING,BLAKE') should give me 2. So I figured a way to split the comma separated string to rows and used that in the procedure.
So if I change the where clause as below to in
create or replace procedure emp_poc2(in_names IN varchar2)
as
cnt integer;
begin
select count(*)
into cnt
from emp1
where
ename in (select trim(regexp_substr(in_names, '[^,]+', 1, level))
from dual
connect by instr(in_names, ',', 1, level - 1) > 0
);
dbms_output.put_line(cnt);
end;
So exec emp_poc2('KING','BLAKE') gives me 2. But passing null will give result as 0. However I want to get 3 like the case with emp_proc
And I cannot use nvl with in as it expect the subquery to return a single value.
1 way I can think of is rebuilding the whole query in a variable, based in input paramteter, and then use execute immediate. But I am using some variables to collect the value and it would be difficult to achieve it with execute immediate.
I am again emphasizing that this is a simple version of a complex procedure where we are capturing many variables and it joins many tables and has multiple AND conditions in where clause.
Any ideas on how to make this work.
This may help you
CREATE OR REPLACE PROCEDURE emp_poc2(in_names IN varchar2)
AS
cnt integer;
BEGIN
SELECT COUNT(*) INTO cnt
FROM emp1
WHERE
in_names IS NULL
OR ename IN (
SELECT TRIM(REGEXP_SUBSTR(in_names, '[^,]+', 1, level))
FROM dual
CONNECT BY INSTR(in_names, ',', 1, level - 1) > 0
);
dbms_output.put_line(cnt);
END;
Other way could be use IF ELSE or UNION ALL
If your real code is much more complex then your code readability might be greatly enhanced by using a proper collection type instead.
In the example below I have created an user defined type str_list_t that is a real collection of strings.
I also use common table expression (CTE) in the sql query to enhance the readability. In this simple example the CTE benefits for readability are not obvious but for all non-trivial queries it's a valuable tool.
Test data
create table emp1(empno number, empname varchar2(10));
insert into emp1 values(5437, 'GATES');
insert into emp1 values(5438, 'JOBS');
insert into emp1 values(5439, 'BEZOS');
insert into emp1 values(5440, 'MUSK');
insert into emp1 values(5441, 'CUBAN');
insert into emp1 values(5442, 'HERJAVEC');
commit;
Supporting data type
create or replace type str_list_t is table of varchar2(4000 byte);
/
Subprogram
create or replace function emp_count(p_emps in str_list_t) return number is
v_count number;
v_is_null_container constant number :=
case
when p_emps is null then 1
else 0
end;
begin
-- you can also test for empty collection (that's different thing than a null collection)
with
-- common table expression (CTE) gives you no benefit in this simple example
emps(empname) as (
select * from table(p_emps)
)
select count(*)
into v_count
from emp1
where v_is_null_container = 1
or empname in (select empname from emps)
;
return v_count;
end;
/
show errors
Example run
SQL> select 2 as expected, emp_count(str_list_t('BALLMER', 'CUBAN', 'JOBS')) as emp_count from dual
union all
select 0, emp_count(str_list_t()) from dual
union all
select 6, emp_count(null) from dual
;
EXPECTED EMP_COUNT
---------- ----------
2 2
0 0
6 6
I want to create a sequence for this varchar. It would have been easier had it been a number instead of varchar. In that case, I could do
seq_no := seq_no + 1;
But what can I do when I want to store next value in column as A0000002, when the previous value was A0000001 (to increment the number in the next varchar rowby 1)?
This can be done by
to_char(seq_no,'FM0000000')
your example can be done by creating sequence in oracle
create sequence seq_no start with 1 increment by 1;
then
select 'A'||to_char(seq_no.nextval,'FM0000000') from dual;
Right now i have used in dual ..but place this
'A'||to_char(seq_no.nextval,'FM0000000')
in your required query ..this will create sequence as you mentioned
sqlfiddle
Sequences are purely numeric. However, you need a trigger anyway, so simply adapt such trigger to insert the desired prefix:
CREATE OR REPLACE TRIGGER FOO_TRG1
BEFORE INSERT
ON FOO
REFERENCING NEW AS NEW OLD AS OLD
FOR EACH ROW
BEGIN
IF :NEW.FOO_ID IS NULL THEN
SELECT 'A' || TO_CHAR(FOO_SEQ1.NEXTVAL, 'FM0000000') INTO :NEW.FOO_ID FROM DUAL;
END IF;
END FOO_TRG1;
/
ALTER TRIGGER FOO_TRG1 ENABLE;
If you're able I'd actually use a virtual column as defined in the CREATE TABLE syntax. It makes it more easily extensible should the need arise.
Here's a working example.
SQL> create table tmp_test (
2 id number(7,0) primary key
3 , col1 number
4 , seq varchar2(8 char) generated always as (
5 'A' || to_char(id, 'FM0999999'))
6 );
Table created.
SQL>
SQL> create sequence tmp_test_seq;
Sequence created.
SQL>
SQL> create or replace trigger tmp_test_trigger
2 before insert on tmp_test
3 for each row
4 begin
5
6 :new.id := tmp_test_seq.nextval;
7 end;
8 /
Trigger created.
SQL> show errors
No errors.
SQL>
SQL> insert into tmp_test (col1)
2 values(1);
1 row created.
SQL>
SQL> select * from tmp_test;
ID COL1 SEQ
---------- ---------- --------------------------------
1 1 A0000001
Having said that; you would be better off if you did not do this unless you have an unbelievably pressing business need. There is little point to making life more difficult for yourself by prepending a constant value onto a number. As A will always be A it doesn't matter whether it's there or not.
If the format is always a letter followed by 7 digits you can do:
sequence = lpad(substr(sequence,2,7)+1,7,'0')
When i ran the below queries it's failing in the second query becuase prev_test_ref1 variable is not defined. If i remove the insert statement in the first query ,run again then it's working and using the prev_test_ref1 value from the first sql query in second query. Is it because of variable scope? How can i resolve this with the insert statement.
QUERY1
column prev_test_ref1 new_value prev_test_ref1 ;
insert into testing.test_ref_details(TEST_TYPE,TEST_REF_NO)
select '1',max(test_ref_no) as prev_test_ref1
from testing.test_runs_status
where test_type = 1
and run_status = 1
and test_end_dt = (select last_day(add_months(trunc(sysdate),-6))+2 from dual)
group by test_end_dt
;
QUERY2
column last_test_end_dt new_value last_test_end_dt;
select to_char(test_completion_dt,'DD-MON-YYYY HH24:MI:SS') as last_test_end_dt
from testing.test_runs_status
where test_ref_no = '&prev_test_ref1';
In SQLPlus substitution variables will only be defined with SELECT statements. Your first insert doesn't return rows so it won't work (think about it: it only returns 1 row inserted., SQLPlus has no way to know the value inserted.)
I suggest you add a step to save the value into the variable (or use a PL/SQL block):
column prev_test_ref1 new_value prev_test_ref1 ;
SELECT MAX(test_ref_no) AS prev_test_ref1
FROM testing.test_runs_status
WHERE test_type = 1
AND run_status = 1
AND test_end_dt = (SELECT last_day(add_months(trunc(SYSDATE), -6)) + 2
FROM dual)
GROUP BY test_end_dt;
INSERT INTO testing.test_ref_details(TEST_TYPE,TEST_REF_NO)
VALUES ('1', &prev_test_ref1);
SELECT ...
declare
prev_test_ref1 number(10);
begin
insert into ...select ...;
select ... into prev_test_ref1 from ...;
end;
/
The INSERT statement has a RETURNING clause. We can use this to get access to "unknown" values from the table. The following examples uses RETURNING to get the assigned nextval from a sequence, but we could return any column from the row:
SQL> var prev_id number
SQL> insert into t23 (id, name) values (my_seq.nextval, 'MAISIE')
2 returning id into :prev_id
3 /
1 row created.
SQL> select * from t23
2 where id = :prev_id
3 /
NAME ID
---------- ----------
MAISIE 122
SQL>
Unfortunately the RETURNING clause only works with single-row SQL.
It isn't really clear what the purpose of the whole script is, especially in light of the comment "i have similar sql query which returns multiple rows. In that case i cant have separate insert statement."
If you want to use the results of a select, see if Multi-Table Inserts fit the bill. Your select statement can insert into both the primary table and also a second table (eg a global temporary table). You can then query the global temporary table to see what rows were inserted.
I saw something like the following in our production code:
select max(col_val) from table_name where
--set of conditions here
--AND
rownum=1;
This looked strange to me. Would the above code execute with the intended purpose?(selecting a max value from a set of values). Won't this select always return a single record from which the col_val would be chosen?. Thanks.
No. It is guarenteed to get the max of a set of values. It will return the first value only, where first value is driven by execution plan. Depending on the plan, the first value may be the max value also, but this could change because plans are not constant.
SQL> create table t (i number);
Table created.
SQL> insert into t values (1);
1 row created.
SQL> insert into t values (2);
1 row created.
SQL> select i from t;
I
----------
1
2
SQL> select max(i) from t;
MAX(I)
----------
2
SQL> select max(i) from t where rownum = 1;
MAX(I)
----------
1
SQL>
it will take the first row that satisfies conditions. max seems to be excess here.