I have this DML statement..
delete from (select key,value,computed, row_number() OVER (Partition By key, value order by seq asc) as a
from excelformats a )
where A > 1
and this throws
ORA-01732: data manipulation operation not legal on this view
This statement basically selects duplicate rows from excelFormats table those to be deleted
How can I revise so that
You could use:
DELETE FROM excelformats
WHERE rowid not in
(SELECT MIN(rowid)
FROM excelformats
GROUP BY key, value, computed);
This will delete duplicate rows in your excelformats table given the three key columns you stated.
Hope it helps...
Related
I'm new to PL\SQL programming and I'm from DBA background. I got one requirement to delete data from both main table and reference table but need to follow below logic while deleting data because we need to delete 30M of data from the tables so we're reducing data based on the "State_ID" column below.
Following conditions need to consider
1. As per sample data given below(Main Table), sort data based on timestamp with desc order and leave the first 2 rows of data for each "State_id" and delete rest of the data from the both tables based on "state_id" column.
2. select state_id,count() from maintable group by state_id order by timestamp desc Having count()>2;
So if state_id=1 has 5 rows then has to delete 3 rows of data by leaving first 2 rows for state_id=1 and repeat for other state_id values.
Also same matching data should be deleted from the reference table as well.
Please someone help me on this issue. Thanks.
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Main table
You should be able to do each table delete as a single SQL command. Anything else would essentially force row-by-row processing, which is the last thing you want for that much data. Something like this:
delete from main_table m
where m.row_id not in (
with keep_me as (
select row_id,
row_number() over (partition by state_id
order by time_stamp desc) id_row_number
from main_table where id_row_number<3)
select row_id from keep_me)
or
delete from main_table m
where m.row_id in (
with delete_me as (
select row_id,
row_number() over (partition by state_id
order by time_stamp desc) id_row_number
from main_table where id_row_number>2)
select row_id from delete_me)
I am using Toad for oracle 12c. I need to copy a table and data (40M) from one shcema to another (prod to test). However there is an unique key(not the PK for this table) called record_Id col which has something data like this 3.000*******19E15. About 2M rows has same numbers(I believe its because very large number) which are unique in prod. When I try to copy it violets the unique key of that col. I am using toad "export data to another schema" function to copy the data.
when I execute query in prod
select count(*) from table_name
OR
select count(distinct(record_id) from table_name
Both query gives the exact same numbers of data.
I don't have DBA permission. How do I copy all data without violating unique key of the table.
Thanks in advance!
You can use UPSERT for decisional INSERT or UPDATE or you may write small procedure for this.
you may consider to use NOT EXISTS, but your data is big and it might not be resource efficient.
insert into prod_tab
select * from other_tab t1 where NOT exists (
select 1 from prod_tab t2 where t1.id = t2.id
);
In Oracle you can use a MERGE query for that.
The following query proceeds as follows for each data row :
if the source record_id does not yet exist in the target table, a new record is inserted
else, the existing record is updated with source values
For the sake of the example, I assumed that there are two other columns in the table : column1 and column2.
MERGE INTO target_table t1
USING (SELECT * from source_table t2)
ON (t1.record_id = t2.record_id)
WHEN MATCHED THEN UPDATE SET
t1.column1 = t2.column1,
t1.column2 = t2.column2
WHEN NOT MATCHED THEN INSERT
(record_id, column1, column2) VALUES (t2.record_id, t2.column1, t2.column2)
I have identified some duplicates in my table:
-- DUPLICATES: ----
select PPLP_NAME,
START_TIME,
END_TIME,
count(*)
from PPLP_LOAD_GENSTAT
group by PPLP_NAME,
START_TIME,
END_TIME
having count(*) > 1
-- DUPLICATES: ----
How is it possible to delete them?
Even if you don't have the primary key, each record has a unique rowid associated.
By using the query below you delete only the records that don't have the maximum row id by self joining a table with the columns that cause duplication. This will make sure that you delete any duplicates.
DELETE FROM PPLP_LOAD_GENSTAT plg_outer
WHERE ROWID NOT IN(
select MAX(ROWID)
from PPLP_LOAD_GENSTAT plg_inner
WHERE plg_outer.pplp_name = plg_inner.pplg_name
AND plg_outer.start_time= plg_inner.start_time
AND plg_outer.end_time = plg_inner.end_time
);
I'd suggest something easier:
CREATE table NewTable as
SELECT DISTINCT pplp_name,start_time,end_time
FROM YourTable
Then delete your table, and rename the new table.
If you really want to delete records, you can find a few examples of how here.
The Primary key in table one is used as in table 2 but it is modified as so:
Primary key Column in table 1: 123abc
Column in table 2: 123abc_1
I.e. the key is used but then _1 is added to create a unique value in the column of Table 2.
Is there any way that I can join the two tables, the data in the 2 columns is not identical but it very similar. Could I do something like:
SELECT *
FROM TABLE1 INNER JOIN
TABLE2
ON TABLE1.COUMN1 contains TABLE2.COLUMN2;
I.e. checking that the value in Table 1 is within the value in Table 2?
You can check only the first part of column2; for example
SELECT *
FROM TABLE1 INNER JOIN TABLE2
ON INSTR(COLUMN2, COLUMN1) = 1
or
ON COLUMN2 LIKE COLUMN1 || '%'
However, keeping foreign key in such a way can be really dangerous, not to think about performance on large DBs.
You'd better use a different column in Table2 to store the key of Table 1, even adding a constraint.
I have a table like this :
How can I sort it out in the form below :
Each set of records has been marked by a FlagID at end
Each set of records has been marked by a FlagID at end
I assume this means that each record is implicitly associated with the first non-null FlagID value that occurs at or after its position along the ID primary key. Thus, we can use a correlated subquery to project this implicit FlagID value for each record, sort by it, then sort by your Row column as tiebreaker for each set.
SELECT *
FROM YourTable T1
ORDER BY
(
SELECT TOP 1 T2.FlagID
FROM YourTable T2
WHERE T2.ID <= T1.ID
AND T2.FlagID IS NOT NULL
ORDER BY T2.ID DESC
),
T1.Row
However, if you're able to alter the database content, I would recommend you to explicitly populate all the FlagID fields, as this would make your life easier. If you do so, then the query becomes:
SELECT *
FROM YourTable T1
ORDER BY T1.FlagID,
T1.Row