So i am trying to update my Vorschlagspakete table with some values i got from other tables. Precisely there are 3 values i want to write into the main table. Atm it looks like this:
update vorschlagspakete
set (paketid, verkaufsstelleid) = (
select k.paketid, k.verkaufsstelleid
from Konfiguration k, bewertung b
where k.konfigurationsid = b.konfigurationsid
group by k.paketid, k.verkaufsstelleid
having avg(b.sterne) >= 5);
But every time i tried this it results into ora-01427.
Error you got, ORA-01427, means too many rows (were returned by subquery). For example based on Scott's schema (as I don't have your tables), it looks like this:
SQL> update emp e set
2 (e.ename, e.job) = (select d.dname, d.loc from dept d);
(e.ename, e.job) = (select d.dname, d.loc from dept d)
*
ERROR at line 2:
ORA-01427: single-row subquery returns more than one row
Why wouldn't it work? Because subquery returns more than a single row!
SQL> select d.dname, d.loc from dept d;
DNAME LOC
-------------- -------------
ACCOUNTING NEW YORK
RESEARCH DALLAS
SALES CHICAGO
OPERATIONS BOSTON
SQL>
So, how would you put all those values into a single row of the EMP table? That won't work, obviously, so you have to do something to restrict number of rows. How? Well, it depends.
sometimes DISTINCT helps, e.g.
select distinct d.dname, d.loc from dept d
sometimes additional WHERE condition helps, e.g.
select d.dname, d.loc from dept d
where d.location = 'NEW YORK'
sometimes joining with the table to be updated helps, e.g.
select d.dname, d.loc from dept d where d.deptno = e.deptno
which leads to
SQL> update emp e set
2 (e.ename, e.job) = (select d.dname, d.loc from dept d where d.deptno = e.deptno);
14 rows updated.
What should you do? I don't know, we don't have your data. See whether something written above helps.
Related
I have a Query where there is number datatype column. In case of empty resultset O/P is blank. I want 0 in that case.
My query is
select nvl(infodata,0)
from table1
where group_id = 111
and appid in (select max(id)
from table1, table2
where status = 'A');
Now my inner query is returning null in that case. NVL seems to be not working on infodata column. Please help
Outcome of such a query is no rows selected.
For example (based on Scott's EMP and DEPT tables as I don't have yours, and you didn't post test case), this query returns nothing:
SQL> select e.deptno
2 from emp e
3 where e.ename = 'Littlefoot';
no rows selected
If it is used as a subquery, the result is equal to what you currently have:
SQL> select nvl(d.dname, 'x') result
2 from dept d
3 where d.deptno in (select e.deptno
4 from emp e
5 where e.ename = 'Littlefoot'
6 );
no rows selected
But, if you apply aggregation (see line #1), then you'd get what you wanted:
SQL> select nvl(max(d.dname), 'x') result
2 from dept d
3 where d.deptno in (select e.deptno
4 from emp e
5 where e.ename = 'Littlefoot'
6 );
RESULT
--------------
x
As I said: it works on my test case; might, or might not on yours. If you post sample data, we'd have something to work with.
How to create a temporary table in oracle without knowing the number and name of columns.
For example:
Select columnA,columnB,* into temp_table from tableA.
Here,tableA maynot be a simple tablename but maybe derived from many queries.
How can this be achieved?Is there any alternative to this?
In Oracle, you have to first create a table, then insert into it. Or, create it directly (as in my example).
Note that I've created a "normal" table; if it were temporary, you could have chosen between a global or private (depending on database version you use).
For this discussion, I guess that it is just fine:
SQL> create table temp_table as
2 select a.*
3 from (select d.deptno, d.dname, e.ename --> this SELECT is your "tableA"
4 from emp e join dept d
5 on e.deptno = d.deptno
6 where job = 'CLERK'
7 ) a;
Table created.
SQL> select * from temp_table;
DEPTNO DNAME ENAME
---------- -------------------- ----------
10 ACCOUNTING MILLER
20 RESEARCH SMITH
20 RESEARCH ADAMS
30 SALES JAMES
SQL>
Alternatively, create a view and work with it:
SQL> create or replace view v_temp as
2 select d.deptno, d.dname, e.ename
3 from emp e join dept d
4 on e.deptno = d.deptno
5 where job = 'CLERK'
6 ;
View created.
SQL> select * from v_temp;
DEPTNO DNAME ENAME
---------- -------------------- ----------
10 ACCOUNTING MILLER
20 RESEARCH SMITH
20 RESEARCH ADAMS
30 SALES JAMES
SQL>
This statement creates temp_table which contains all columns and data from tableA and two other empty columns, varchar and numeric.
create table temp_table as
select cast (null as varchar2(10)) columnA,
cast (null as number(6)) columnB,
tableA.*
from tableA
If you need only structure, no data, then add:
where 1 = 0
I am not sure why you want to have a temp table as you do not know columns, but you can think of dynamic SQL to create table depending on columns required during your process and then drop it again. From my point of view I think it is not a good design.
I can suggest to think on using collection with 'x' number of columns with datatype as VARCHAR2. During transaction you can populate and process according to you need and it will also remain for that session.
I have two tables and I need to Update the second table with a value from first table based on a common column.
I used the below statement
UPDATE emp
2 SET ename = ( SELECT dname
3 FROM dept
4 WHERE emp.deptno = dept.deptno)
5 WHERE EXISTS
6 ( SELECT dname
7 FROM dept
8 WHERE emp.deptno = dept.deptno);
But am getting the error
ORA-01427 - Single row subquery returns more than one row.
Can you plese help me out?
SELECT dname
FROM dept
WHERE emp.deptno = dept.deptno
query must return single record.
check with
SELECT count(*), dname
FROM dept
group by dname
having count(*) > 1
order by 1 desc
or use
SELECT dname
FROM dept
WHERE emp.deptno = dept.deptno
and rownum = 1
You need to check if 1st subquery returns only 1 value bcz if this subquery returns more then 1 row you want to update 1 field ename with 2 values from row and that's why i guess you have this error
Your subquery to dept table is probably not returning one row. Add min or max operation to get one row from dept for each row from emp. Each setting value must be nonambigous.
UPDATE emp
SET ename = ( SELECT min dname
FROM dept
WHERE emp.deptno = dept.deptno)
WHERE EXISTS
( SELECT dname
FROM dept
WHERE emp.deptno = dept.deptno);
Remark1: in default SCOTT schema deptno is primary key, so no error would be encountered.
Remark2: shouldn't your question to be placed in serverfault.com?
I was given a query to explain. Could someone please explain it to me:
select j.ip_num from
jobs j, address a
where j.jobtype='C' and
a.sel_code(+)='H' and
j.ip_num=a.ip_num and
a.ip_num is null order by a.ip_num
That query selects every JOB.IP_NUM which doesn't have a matching ADDRESS record or where the matching ADDRESS record has a SEL_CODE not equal to 'H'.
The (+) is Oracle's old outer join syntax. It is the only OUTER JOIN syntax supported in versions of Oracle before 9i.
In this query we get one row for every row in EMP which matches a department, plus a row for the DEPTNO=40, which has no employees:
SQL> select d.dname
2 , e.ename
3 from dept d
4 , emp e
5 where d.deptno = e.deptno(+)
6 /
DNAME ENAME
-------------- ----------
ACCOUNTING SCHNEIDER
ACCOUNTING BOEHMER
ACCOUNTING KISHORE
RESEARCH ROBERTSON
RESEARCH KULASH
RESEARCH GASPAROTTO
RESEARCH RIGBY
RESEARCH CLARKE
SALES HALL
SALES CAVE
SALES SPENCER
SALES BILLINGTON
SALES PADFIELD
SALES VAN WIJK
SALES KESTELYN
SALES LIRA
OPERATIONS PSMITH
HOUSEKEEPING VERREYNNE
HOUSEKEEPING FEUERSTEIN
HOUSEKEEPING PODER
HOUSEKEEPING TRICHLER
COMMUNICATIONS
22 rows selected.
SQL>
Now, if we put an additional filter on the EMP table like this, we simply get one record for each Department, because only one record in EMP now matches:
SQL> select d.dname
2 , e.ename
3 from dept d
4 , emp e
5 where d.deptno = e.deptno(+)
6 and e.ename(+) = 'CAVE'
7 /
DNAME ENAME
-------------- ----------
ACCOUNTING
RESEARCH
SALES CAVE
OPERATIONS
HOUSEKEEPING
COMMUNICATIONS
6 rows selected.
SQL>
/
To convert this query into the ANSI SQL syntax we have to do this:
SQL> select d.dname
2 , e.ename
3 from dept d
4 left outer join emp e
5 on ( d.deptno = e.deptno
6 and e.ename = 'CAVE' )
7 /
DNAME ENAME
-------------- ----------
ACCOUNTING
RESEARCH
SALES CAVE
OPERATIONS
HOUSEKEEPING
COMMUNICATIONS
6 rows selected.
SQL>
Note that if we don't include the additonal clause in the JOIN but leave it in the WHERE clause we get a different result:
SQL> select d.dname
2 , e.ename
3 from dept d
4 left outer join emp e
5 on ( d.deptno = e.deptno )
6 where e.ename = 'CAVE'
7 /
DNAME ENAME
-------------- ----------
SALES CAVE
SQL>
This is the equivalent of omitting the (+) in the second old skool query.
The query is joining the 2 tables jobs, and address. These tables are joining on the field ip_num but you are looking for the records that exist in the jobs table but do not exist in the address table.
This is a LEFT OUTER JOIN. This query could also be written
SELECT j.ip_num
FROM jobs j
LEFT OUTER JOIN address a
ON j.ip_num=a.ip_num
WHERE j.jobtype='C' AND
a.sel_code(+)='H' AND
a.ip_num is null
ORDER BY a.ip_num
It might be useful to see a visual picture joins http://www.codinghorror.com/blog/2007/10/a-visual-explanation-of-sql-joins.html
I have the following code that works fine in MS SQL Server:
delete grp
from grp
left join my_data
on grp.id1 = my_data.id1
and grp.id2 = my_data.id2
and grp.id3 = my_data.id3
and grp.id4 = my_data.id4
where my_data.id1 is NULL
Basically, I want to delete all occurrence that can be found in grp and don't have any equivalence in my_data. Sadly, it doesn't work in Oracle 10g. I tried using the old syntax for left join (+) but it doesn't work either. Like this:
delete grp
from grp,
my_data
where grp.id1 = my_data.id1 (+)
and grp.id2 = my_data.id2 (+)
and grp.id3 = my_data.id3 (+)
and grp.id4 = my_data.id4 (+)
and my_data.id1 is NULL
A IN clause would works if I didn't have multiple keys but I don't see how I could use it with my data. So, what is the alternative?
Shannon's solution is the way to go: use the operator NOT IN (or NOT EXISTS).
You can however delete or update a join in Oracle, but the synthax is not the same as MS SQL Server:
SQL> DELETE FROM (SELECT grp.*
2 FROM grp
3 LEFT JOIN my_data ON grp.id1 = my_data.id1
4 AND grp.id2 = my_data.id2
5 AND grp.id3 = my_data.id3
6 AND grp.id4 = my_data.id4
7 WHERE my_data.id1 IS NULL);
2 rows deleted
Additionally, Oracle will only let you update a join if there is no ambiguity as to which base row will be accessed by the statement. In particular, Oracle won't risk an update or a delete (the statement will fail) if there is a possibility that a row may appear twice in the join. In this case, the delete will only work if there is a UNIQUE constraint on my_data(id1, id2, id3, id4).
Tables and data:
SQL> create table grp (id1 number null, id2 number null, id3 number null, id4 number null);
Table created.
SQL> create table my_data (id1 number null, id2 number null, id3 number null, id4 number null);
Table created.
SQL> insert into grp values (1, 2, 3, 4);
1 row created.
SQL> insert into grp values (10, 20, 30, 40);
1 row created.
SQL> insert into grp values (1, 2, 30, 40);
1 row created.
SQL> insert into my_data values (1, 2, 3, 4);
1 row created.
SQL> commit;
Commit complete.
Using in. Note Do not use if the IDs in the subquery can be null. Not in of null never returns true.
SQL> delete grp where (id1, id2, id3, id4) not in (select id1, id2, id3, id4 from my_data);
2 rows deleted.
SQL> select * from grp;
ID1 ID2 ID3 ID4
---------- ---------- ---------- ----------
1 2 3 4
Using exists
SQL> rollback;
Rollback complete.
SQL> delete grp where not exists (select * from my_data where grp.id1 = my_data.id1 and grp.id2 = my_data.id2 and grp.id3 = my_data.id3 and grp.id4 = my_data.id4);
2 rows deleted.
SQL> select * from grp;
ID1 ID2 ID3 ID4
---------- ---------- ---------- ----------
1 2 3 4
SQL>
If you want to ensure there is no ambiguity in what's being deleted, you could change Vincent's solution to:
delete from grp where rowid in
(
select
grp.rowid
from
grp left outer join my_data on
grp.id1 = my_data.id1
and grp.id2 = my_data.id2
and grp.id3 = my_data.id3
and grp.id4 = my_data.id4
where
my_data.id1 is NULL
)
Either Vincent's answer https://stackoverflow.com/a/3675205 does not work at all, or it does not work in Oracle 12c. That answer should be improved by specifying the lowest or highest version of Oracle where this works. The proof:
SELECT * FROM v$version where banner like 'Oracle%';
/*
Oracle Database 12c Standard Edition Release 12.2.0.1.0 - 64bit Production
*/
create table a (id int);
create table b (id int);
insert into a select 1 from dual union select 2 from dual;
insert into b select 1 from dual union select 2 from dual union select 3 from dual;
select * from a right join b on b.id = a.id;
/*
1 1
2 2
null 3
*/
delete from (
select b.*
from b
inner join a on a.id = b.id
)
/*
Error at Command Line : 7 Column : 13
Error report -
SQL Error: ORA-01752: cannot delete from view without exactly one key-preserved table
01752. 00000 - "cannot delete from view without exactly one key-preserved table"
*Cause: The deleted table had
- no key-preserved tables,
- more than one key-preserved table, or
- the key-preserved table was an unmerged view.
*Action: Redefine the view or delete it from the underlying base tables.
*/
delete from b
where rowid in (
select b.rowid
from b
inner join a on a.id = b.id
)
/*
2 rows deleted.
*/
select * from a right join b on b.id = a.id
/*
null 3
*/
drop table a;
drop table b;
Bottom line is, use WHERE ROWID IN () at least in 12c.
I can't add a comment because it need 50 reps,so I add a answer here.
I tested Vincent's delete from query, that syntax can't let you delete what you want,at least it's not a common use for all the delete join cases.
At first I create a table using oracle default user scott:
create table emp1 as select * from emp where sal<2000;
I want to delete the records from emp where empno in emp1(just a simple test),so I used this delete from query:
delete from (select a.* from emp a join emp1 b on a.empno=b.empno);
No matter what the table or join order is,left join or inner join,no matter what where clause I use,the sql will delete the corresponding records in emp1.
So I think this delete from query can not let you delete from a specified table.
Loop a cursor will be a better way for these cases.