Loop Insert Date a daily commit day to day timestamp ORACLE - oracle

Question

im executing query in oracle. i need insert data everyday commit in looping like this :
DECLARE
start_date NUMBER;
end_date NUMBER;
business_date VARCHAR2 (8);
BEGIN
start_date := TO_NUMBER (TO_CHAR (TO_DATE ('2017-01-01', 'yyyy-MM-dd')));
end_date := TO_NUMBER (TO_CHAR (TO_DATE ('2018-01-01', 'yyyy-MM-dd')));
FOR cur_r IN start_date .. end_date
LOOP
INSERT INTO file_backup
SELECT *
FROM file_core
WHERE TO_NUMBER (TO_CHAR (TO_DATE (datecreated, 'yyyy-MM-dd')))>=start_date+cur_r
AND TO_NUMBER (TO_CHAR (TO_DATE (datecreated, 'yyyy-MM-dd')))<=end_date;
COMMIT;
END LOOP;
END;
I dunt know error this script .. please help me .. btw i newbie in oracle sorry ..

Answer 1

As #boneist pointed out, your manipulation using numbers isn't going to work. You should keep the data type as it is and compare with values of the same data type.
Assuming you have a legitimate need to do this in a loop you could do something like this:
BEGIN
FOR r IN (
select date '2017-01-01' + level -1 as this_date
from dual
connect by level <= date '2018-01-01' - date '2017-01-01'
)
LOOP
INSERT INTO file_backup
SELECT *
FROM file_core
WHERE datecreated >= r.this_date
AND datecreated < r.this_date + 1;
COMMIT;
END LOOP;
END;
/
Or if the data type is actually a timestamp rather than a date as suggested in a comment, something like:
BEGIN
FOR r IN (
select timestamp '2017-01-01 00:00:00'
+ (level -1) * interval '1' day as this_timestamp
from dual
connect by level <= extract(day from timestamp '2018-01-01 00:00:00'
- timestamp '2017-01-01 00:00:00')
)
LOOP
INSERT INTO file_backup
SELECT *
FROM file_core
WHERE datecreated >= r.this_timestamp
AND datecreated < r.this_timestamp + interval '1' day;
COMMIT;
END LOOP;
END;
/
... though you might want to work on the condition for the connect-by query, e.g.
FOR r IN (
select timestamp '2017-01-01 00:00:00'
+ numtodsinterval(level -1, 'DAY') as this_timestamp
from dual
connect by timestamp '2017-01-01 00:00:00'
+ numtodsinterval(level -1, 'DAY') < timestamp '2018-01-01 00:00:00'
)
LOOP
...
or as #boneist suggested in a comment, with a simpler loop:
BEGIN
FOR num_days in 0..(date '2018-01-01' - date '2017-01-01' - 1)
LOOP
INSERT INTO file_backup
SELECT *
FROM file_core
WHERE datecreated >= timestamp '2017-01-01 00:00:00'
+ numtodsinterval(num_days, 'DAY')
AND datecreated < timestamp '2017-01-01 00:00:00'
+ numtodsinterval(num_days + 1, 'DAY');
COMMIT;
END LOOP;
END;
/
The main problem with this approach is restartability. If there is an error part way through the loop you can't just re-run it, as you'd be inserting duplicates.
Multiple inserts and commits are also less efficient that a single insert, or even multiple inserts and a single commit. If you don't have enough undo space to allow a single transaction to do all the work you need you should be fixing the database configuration to allow that, rather than working around it and potentially compromising data integrity.
i need backup this table . and insert only 2 month in new table
That sounds like you need to partition the table by month and use partition swaps to shift old months from the live to the backup table, perhaps. Partitioning costs more but if you have those data volumes it may be justified.
Failing that you could consider renaming your current table to backup, recreating your original table, and just copying the two months' worth of data you want to keep back to that. But that's a one-off thing, you still have the ongoing problem of ageing records out of the main table and into backup. And it has its own issues with dependencies, constraints, etc.

Answer 2

You don't need any loop and you should skip all these TO_CHAR, TO_NUMBER, TO_DATE conversions. Try this:
INSERT INTO file_backup
SELECT *
FROM file_core
WHERE datecreated BETWEEN DATE '2017-01-01' AND DATE '2018-01-01';
Perhaps datecreated has time values different to 00:00:00, in this case you should run
INSERT INTO file_backup
SELECT *
FROM file_core
WHERE TRUNC(datecreated) BETWEEN DATE '2017-01-01' AND DATE '2018-01-01';
or in case datecreated is a VARCHAR2 data type rather than DATE run
INSERT INTO file_backup
SELECT *
FROM file_core
WHERE TO_DATE(datecreated, 'YYYY-MM-DD') BETWEEN DATE '2017-01-01' AND DATE '2018-01-01';

Answer 3

Assuming your datecreated column is of data type DATE and you only want one copy of the rows of the table then you do not need PL/SQL:
INSERT INTO file_backup
SELECT *
FROM file_core
WHERE datecreated BETWEEN DATE '2017-01-01' AND DATE '2018-01-01';
COMMIT;

Answer 4

You could use a DATE literal to set the start_date and end_date and use a loop like this.
DECLARE
start_date NUMBER;
end_date NUMBER;
BEGIN
start_date := DATE '2017-01-01';
end_date := DATE '2018-01-01';
FOR cur_r IN 0 .. (end_date - start_date)
LOOP
INSERT INTO file_backup
SELECT *
FROM file_core
WHERE TRUNC (datecreated) = start_date + cur_r;
COMMIT;
END LOOP;
END;

Answer 5

Why wouldn't you do it using a simple INSERT, such as
INSERT INTO file_backup
SELECT *
FROM file_core
WHERE datecreated BETWEEN DATE '2017-01-01' AND DATE '2018-01-01';
If you're just practicing PL/SQL and loops, well, remove COMMIT out of the LOOP. Both START and END_DATE should be "converted" to a number using a proper format mask (i.e. yyyymmdd). FOR loop's index should go from 1 to a difference between END and START_DATE.
[EDITED, after reading MT0's comment]
[EDITED #2, after reading some more comments]
Bah, my code is rubbish, should've thought about what I'm doing. Basically, if I meant to write it properly, it would have looked like #Kaushik Nayak's, and there's really no point in doing it twice.