I have two records below. I was trying to pull the latest record based from the Sold_DT, which would give me the record with 7 in Item column.
Store Sold_DT Item
CVS 1/22/2017 12:05:00 AM 5
CVS_S_Eleven 1/22/2017 10:41:00 AM 7
Here is my attempted query in Oracle:
select
store,
max(sold_dt) as max_dt,
item
from temp
group by store, item
Would someone please point me to the correct direction so that I can return only the latest Sold_DT? which is only this:
Store Sold_DT Item
CVS_S_Eleven 1/22/2017 10:41:00 AM 7
Try the MIN/MAX with KEEP. As mathguy points out, if you have two stores tied for most recent, it will get tricky and you are best to add a tiebreaker if you want a single consistent record, or use another technique if you want all ties.
select
max(store) keep (DENSE_RANK FIRST ORDER BY sold_dt desc) max_store,
max(sold_dt) as max_dt,
max(item) keep (DENSE_RANK FIRST ORDER BY sold_dt desc) max_item
from temp
You can take max of sold date from subquery like below and join with main table on that date value
select t1.* from
from temp t1 join (select
max(sold_dt) as max_dt, item
from temp) t2 on t1.Max_dt=t2sold_dt
I wasn't sure if you only wanted one row if there are two with the same date and time. I assumed that you only want one. Of course, in this case there is only one row with max date anyway.
SQL>
SQL> drop table temp;
Table dropped.
SQL>
SQL> create table temp
2 (
3 Store varchar2(12),
4 Sold_DT date,
5 Item number
6 );
Table created.
SQL>
SQL> insert into temp values ('CVS',to_date('01/22/2017 12:05:00 AM','MM/DD/YYYY HH:MI:SS AM'),5);
1 row created.
SQL> insert into temp values ('CVS_S_Eleven',to_date('01/22/2017 10:41:00 AM','MM/DD/YYYY HH:MI:SS AM'),7);
1 row created.
SQL>
SQL> commit;
Commit complete.
SQL>
SQL> select
2 store,
3 Sold_DT,
4 item
5 from temp
6 where
7 Sold_DT = (select max(Sold_DT) from temp) and
8 rownum < 2;
STORE SOLD_DT ITEM
------------ --------- ----------
CVS_S_Eleven 22-JAN-17 7
SQL>
SQL> spool off
Related
I am trying to Create a list partition Based on the column "REFRESH_FLAG_Y" which has only Y and N as its Values, Below is the Alter Table used to Create the partition
ALTER TABLE "EDW"."LABOR_SCHEDULE_DAY_F" MODIFY
PARTITION BY LIST ("REFRESH_FLAG")
(PARTITION "REFRESH_FLAG_Y" VALUES ('Y') ,
PARTITION "REFRESH_FLAG_N" VALUES ('N')) ;
COMMIT;
But Whenever I execute the code I get an Error message
ERROR at line 1:
ORA-14400: inserted partition key does not map to any partition
You did tag the question with Oracle 11g tag; do you really use it?
This is a 12c example; it works if everything is OK:
SQL> create table labor_schedule_day_f as
2 select 1 id, 'Y' refresh_flag from dual union all
3 select 2 id, 'N' refresh_flag from dual;
Table created.
SQL> alter table labor_schedule_Day_f modify
2 partition by list (refresh_flag)
3 (partition refresh_flag_y values ('Y'),
4 partition refresh_flag_n values ('N')
5 );
Table altered.
Error you reported means this:
SQL> drop table labor_schedule_day_f;
Table dropped.
SQL> create table labor_schedule_day_f as
2 select 1 id, 'Y' refresh_flag from dual union all
3 select 2 id, 'N' refresh_flag from dual;
Table created.
Insert a row whose REFRESH_FLAG isn't Y nor N (so it violates the rule you specified):
SQL> insert into labor_schedule_day_f values (3, 'X');
1 row created.
Using the same ALTER TABLE statement as previously:
SQL> alter table labor_schedule_Day_f modify
2 partition by list (refresh_flag)
3 (partition refresh_flag_y values ('Y'),
4 partition refresh_flag_n values ('N')
5 );
alter table labor_schedule_Day_f modify
*
ERROR at line 1:
ORA-14400: inserted partition key does not map to any partition
SQL>
See? Error you got, which means that
which has only Y and N as its Values
isn't true.
P.S. You'd get the same result even if refresh_flag was NULL for some rows.
select rownum into v_rownum
from waitlist
where p_callnum=callnum
order by sysdate;
tried doing this but gives too many values.
and if I do p_snum=snum, it will keep returning 1. I need it to return 2 if it's #2 on the waitlist.
select rn into v_rownum
from (select callnum,
row_number() over (order by sysdate) rn
from waitlist)
where p_snum=snum;
Almost got it to work. Running into issues in the first select. I believe I might have to use v_count instead. Also Ordering by Sysdate even if a second apart will order it correctly.
SNU CALLNUM TIME
--- ---------- ---------
101 10125 11-DEC-18
103 10125 11-DEC-18
BTW time is = date which I entered people into waitlist using sysdate. So I suppose ordering by time could work.
create table waitlist(
snum varchar2(3),
callnum number(8),
time date,
constraint fk_waitlist_snum foreign key(snum) references students(snum),
constraint fk_waitlist_callnum foreign key(callnum) references schclasses(callnum),
primary key(snum,callnum)
);
is the waitlist table.
I used Scott's DEPT table to create your WAITLIST; department numbers represent CALLNUM column:
SQL> select * From waitlist;
CALLNUM WAITER
---------- --------------------
10 ACCOUNTING
20 RESEARCH
30 SALES
40 OPERATIONS
How to fetch data you need?
using analytic function (ROW_NUMBER) which orders values by CALLNUMs, you'll know the order
that query will be used as an inline view for the main query that returns number in the waitlist for any CALLNUM
Here's how:
SQL> select rn
2 from (select callnum,
3 row_number() over (order by callnum) rn
4 from waitlist
5 )
6 where callnum = 30;
RN
----------
3
SQL>
rownum in oracle is a generated column, it does not refer to any specific row, it is just the nth row in a set.
With a select into it can only return one row (hence the two many rows error) so rownum will always be 1.
Without more details about your table structure, and how you are uniquely identifying records it is hard to give assist you further with a solution.
The situation is that, when I import a file into the database, one of the first thing I usually do is to assign an unique ID for each record.
I normally do below in TSQL
ALTER TABLE MyTable
ADD ID INT IDENTITY(1,1)
I am wondering if there is something similar in PL SQL?
All my search result come back with multiple steps.
Then I'd like to know what PL SQL programmer typically do to ID records after importing a file. Do they do that?
The main purpose for me to ID these records is to trace it back after manipulation/copying.
Again, I understand there is solution there, my further question is whether PL SQL programmer actually do that, or there is other alternative which making this step not necessary in PL SQL?
OK then, as you're on Oracle 11g, there's no identity column there so - back to multiple steps. Here's an example:
I'm creating a table that simulates your imported table:
SQL> create table tab_import as
2 select ename, job, sal
3 from emp
4 where deptno = 10;
Table created.
Add the ID column:
SQL> alter table tab_import add id number;
Table altered.
Create a sequence which will be used to populate the ID column:
SQL> create sequence seq_imp;
Sequence created.
Update current rows:
SQL> update tab_import set
2 id = seq_imp.nextval;
3 rows updated.
Create a trigger which will take care about future inserts (if any):
SQL> create or replace trigger trg_bi_imp
2 before insert on tab_import
3 for each row
4 begin
5 :new.id := seq_imp.nextval;
6 end;
7 /
Trigger created.
Check what's in the table at the moment:
SQL> select * from tab_import;
ENAME JOB SAL ID
---------- --------- ---------- ----------
CLARK MANAGER 2450 1
KING PRESIDENT 5000 2
MILLER CLERK 1300 3
Let's import some more rows:
SQL> insert into tab_import (ename, job, sal)
2 select ename, job, sal
3 from emp
4 where deptno = 20;
3 rows created.
The trigger had silently populated the ID column:
SQL> select * From tab_import;
ENAME JOB SAL ID
---------- --------- ---------- ----------
CLARK MANAGER 2450 1
KING PRESIDENT 5000 2
MILLER CLERK 1300 3
SMITH CLERK 800 4
JONES MANAGER 2975 5
FORD ANALYST 3000 6
6 rows selected.
SQL>
Shortly: you need to
alter table and add the ID column
create a sequence
create a trigger
The end.
The answer given by #Littlefoot would be my recommendation too - but still I thought I could mention the following variant which will work only if you do not intend to add more rows to the table later.
ALTER TABLE MyTable add id number(38,0);
update MyTable set id = rownum;
commit;
My test:
SQL> create table tst as select * from all_tables;
Table created.
SQL> alter table tst add id number(38,0);
Table altered.
SQL> update tst set id = rownum;
3815 rows updated.
SQL> alter table tst add constraint tstPk primary key (id);
Table altered.
SQL>
SQL> select id from tst where id < 15;
ID
----------
1
2
3
4
5
6
7
8
9
10
11
ID
----------
12
13
14
14 rows selected.
But as mentioned initially,- this only fixes numbering for the rows you have at the time of the update - your'e not going to get new id values for new rows anytime later - if you need that, go for the sequence solution.
You can add an id column to a table with a single statement (Oracle 11g, see dbfiddle):
alter table test_
add id raw( 16 ) default sys_guid() ;
Example:
-- create a table without an id column
create table test_ ( str )
as
select dbms_random.string( 'x', 16 )
from dual
connect by level <= 10 ;
select * from test_ ;
STR
ULWL9EXFG6CIO72Z
QOM0W1R9IJ2ZD3DW
YQWAP4HZNQ57C2UH
EETF2AXD4ZKNIBBF
W9SECJYDER793MQW
alter table test_
add id raw( 16 ) default sys_guid() ;
select * from test_ ;
STR ID
ULWL9EXFG6CIO72Z 0x782C6EBCAE2D7B9FE050A00A02005D65
QOM0W1R9IJ2ZD3DW 0x782C6EBCAE2E7B9FE050A00A02005D65
YQWAP4HZNQ57C2UH 0x782C6EBCAE2F7B9FE050A00A02005D65
EETF2AXD4ZKNIBBF 0x782C6EBCAE307B9FE050A00A02005D65
W9SECJYDER793MQW 0x782C6EBCAE317B9FE050A00A02005D65
Testing
-- Are the id values unique and not null? Yes.
alter table test_
add constraint pkey_test_ primary key ( id ) ;
-- When we insert more rows, will the id be generated? Yes.
begin
for i in 1 .. 100
loop
insert into test_ (str) values ( 'str' || to_char( i ) ) ;
end loop ;
end ;
/
select * from test_ order by id desc ;
-- last 10 rows of the result
STR ID
str100 0x782C806E16A5E998E050A00A02005D81
str99 0x782C806E16A4E998E050A00A02005D81
str98 0x782C806E16A3E998E050A00A02005D81
str97 0x782C806E16A2E998E050A00A02005D81
str96 0x782C806E16A1E998E050A00A02005D81
str95 0x782C806E16A0E998E050A00A02005D81
str94 0x782C806E169FE998E050A00A02005D81
str93 0x782C806E169EE998E050A00A02005D81
str92 0x782C806E169DE998E050A00A02005D81
str91 0x782C806E169CE998E050A00A02005D81
Regarding your other questions:
{1} Then I'd like to know what PL SQL programmer typically do to ID records after importing a file. Do they do that? The main purpose for me to ID these records is to trace it back after manipulation/copying.
-> As you know, the purpose of an id is: to identify a row. We don't "do anything to IDs". Thus, your usage of IDs seems legit.
{2} Again, I understand there is solution there, my further question is whether PL SQL programmer actually do that, or there is other alternative which making this step not necessary in PL SQL?
-> Not quite sure what you are asking here. Although there is a ROWID() pseudocolumn (see documentation), we should not use it to identify rows.
"You should not use ROWID as the primary key of a table. If you delete
and reinsert a row with the Import and Export utilities, for example,
then its rowid may change. If you delete a row, then Oracle may
reassign its rowid to a new row inserted later."
I want to select a data and wanna see in which partition.
partition column is : code (varchar column)
Select .... -- I want to find partition name
from
partition_table
where to_number(code) = 55;
why I need to this:
I have a data which code is '55' but in that table when I use partition column I do not select it. But there is data which value is '55'
So I want to that data in which partition.
And the data is not in PDEFAULT partition. I ve already check it.
edit
data is in another partition. I think there is a problem with exchange partition process
thanks in advance
There are a couple of ways.
1) The rowid will point to the partition object
SQL> create table t ( x int, y int )
2 partition by range (x )
3 ( partition p1 values less than ( 100 ),
4 partition p2 values less than ( 200 )
5 );
Table created.
SQL>
SQL> insert into t values (34,34);
1 row created.
SQL>
SQL> select rowid from t;
ROWID
------------------
AAA0cqAAHAAAAQ6AAA
1 row selected.
SQL>
SQL> select dbms_rowid.rowid_object(rowid) from t;
DBMS_ROWID.ROWID_OBJECT(ROWID)
------------------------------
214826
1 row selected.
SQL>
SQL> select subobject_name
2 from user_objects
3 where data_Object_id =
4 ( select dbms_rowid.rowid_object(rowid) from t );
SUBOBJECT_NAME
------------------------------------------------------------
P1
2) You can data mine the dictionary to probe the HIGH_VALUE column in USER_TAB_PARTITIONS. I did a video on how to do that here
https://www.youtube.com/watch?v=yKHQQXKdfOM
I'm in the middle of creating a tool similar to the SQL Developer table data viewer. My db is Oracle based.
I simply need to delete eg.: 'row number 3' from a SELECT result. That table doesn't have any PK nor unique records. I've tried various techniques with ROWNUM etc. but no luck.
Oracle has a ROWID pseudocolumn that you can use for this purpose in simple cases.
select rowid, ... from your_table where ... ;
delete from your_table where rowid = <what you got above>;
If your interface allows the user to make complex views/joins/aggregates, then knowing what the user intended to delete (so knowing what set of rowids to gather and what set of tables to delete from) is going to be tricky.
Warning: rowids are unique only within a given table, and, quoting the above documentation:
If you delete a row, then Oracle may reassign its rowid to a new row inserted later.
So be very, very careful if you do this.
Assuming that it is a standard heap-organized table (index-organized tables and clusters potentially introduce additional complexity), if you don't have any other way to identify a row, you can use the ROWID pseudocolumn. This gives you information about the physical location of a row on disk. This means that the ROWID for a particular row can change over time and the ROWID can and will be reused when you delete a row and then a subsequent INSERT operation inserts a new row that happens to be in the same physical location on disk. For most applications, it is reasonable to assume that the ROWID will remain constant between the time that you execute the query and the time that you issue the DELETE but you shouldn't try to store the ROWID for any period of time.
For example, if we create a simple two-column table and a few rows
SQL> create table foo( col1 number, col2 varchar2(10) );
Table created.
SQL> insert into foo values( 1, 'Justin' );
1 row created.
SQL> insert into foo values( 1, 'Justin' );
1 row created.
SQL> insert into foo values( 2, 'Bob' );
1 row created.
SQL> insert into foo values( 2, 'Charlie' );
1 row created.
SQL> commit;
Commit complete.
We can SELECT the ROWID and then DELETE the third row using the ROWID
SQL> select *
2 from foo;
COL1 COL2
---------- ----------
1 Justin
1 Justin
2 Bob
2 Charlie
SQL> select rowid, col1, col2
2 from foo;
ROWID COL1 COL2
------------------ ---------- ----------
AAAfKXAAEAABt7vAAA 1 Justin
AAAfKXAAEAABt7vAAB 1 Justin
AAAfKXAAEAABt7vAAC 2 Bob
AAAfKXAAEAABt7vAAD 2 Charlie
SQL> delete from foo where rowid = 'AAAfKXAAEAABt7vAAC';
1 row deleted.
SQL> select * from foo;
COL1 COL2
---------- ----------
1 Justin
1 Justin
2 Charlie
Try using ROWID instead of ROWNUM.