I have an oracle database that I like to retrieve last days or last 10 minutes data:
I am ussing this command first:
alter session set nls_date_format='dd-mm-yyyy hh24:mi:ss'
Then this:
select TIMESTAMP, TARGET_NAME, TARGET_TYPE, COLUMN_LABEL, VALUE, KEY_VALUE from METRIC_TABLE where TIMESTAMP > sysdate -1
This command is not giving me last days of data, it only gives me last couple hours of data. I suspect that TIMESTAMP column is not in Oracle datatime format.
Is there a way to format TIMESTAMP to Oracle timestamp format before doing this:
TIMESTAMP>SYSDATE -1
Presuming your TIMESTAMP column contains an ordinary date/time variable:
SELECT whatever FROM table WHERE TIMESTAMP >= SYSDATE -1
gets everything that's newer than 24 hours ago.
SELECT whatever FROM table WHERE TIMESTAMP >= SYSDATE - (10.0 / 1440.0)
gets everything that's newer than ten minutes ago.
SELECT whatever FROM table WHERE TIMESTAMP >= TRUNC(SYSDATE)
gets everything newer than midnight last night.
SELECT whatever FROM table WHERE TIMESTAMP >= TRUNC(SYSDATE) -1
AND TIMESTAMP < TRUNC(SYSDATE)
gets everything from yesterday.
Edit Pro tip: don't use reserved words, like TIMESTAMP, for column names.
Try figuring out how many records you have for each hour in the last 5 days like this:
SELECT TO_CHAR(TRUNC(timestamp, 'HH24'), 'DD-MON-YYYY HH24:MI:SS') hr,
COUNT(*)
FROM METRIC_TABLE
WHERE timestamp >= TRUNC(sysdate) -5
GROUP BY TRUNC(timestamp, 'HH24')
That will help you understand what timestamp values you have in your database.
Related
I'm just trying to fetch Hour of my table from created date in Oracle 12c Database but it is showing error INVALID EXTRACT FIELD FOR EXTRACT FIELD. kindly guide me to fetch hour of my date my code is here...
SELECT
EXTRACT( HOUR FROM (TO_CHAR(CREATED_DATE,'RRRR-MM-DD HH:MI:SS')) ) HOUR
FROM
INVOICE_V;
my Date is stored as 6/1/2020 4:04:50 PM in this format and Extract function is not accept this function.
Do not store dates as strings.
But, since you have, convert it from a string to a date using TO_DATE:
SELECT EXTRACT( HOUR FROM TO_TIMESTAMP(CREATED_DATE,'DD/MM/YYYY HH12:MI:SS AM') ) AS HOUR
FROM INVOICE_V;
If, however, you meant that its just displaying in that format (and is actually a DATE data type) then CAST the date to a timestamp:
SELECT EXTRACT( HOUR FROM CAST( CREATED_DATE AS TIMESTAMP) ) AS HOUR
FROM INVOICE_V;
An hour can not be used in the EXTRACT function.
The only way to extract hour is to use TO_CHAR or subtract it from TRUNC date as follows:
TO_CHAR(created_date,'HH24') -- OR 'HH' as per your requirement
-- OR
FLOOR(24*(created_date- TRUNC(created_date)))
Please note that Oracle does not store dates in any format. It has its own binary representation. What you see while selecting from the table is based on the NLS_DATE_FORMAT parameter.
You can set it according to your requirement.
ALTER SESSION SET NLS_dATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS'; -- like this
If you have a date column (or the-like), then:
select extract(hour from cast(created_date as timestamp)) as hr
from invoice_v
Alternatively:
select to_char(created_date, 'hh24') as hr
from invoice_v
The first expression returns an integer number, while the second produces a string.
Note that hour is a language keyword, hence not a good choice for an identifier (here, you used it as a column alias). I changed that.
I need to compare date with date of current day, using SYSDATE, something like this:
SELECT * FROM my_table
WHERE date_column BETWEEN TO_DATE(SYSDATE -3,'dd.mm.yyyy') AND TO_DATE(SYSDATE,'dd.mm.yyyy');
However, this produces no result....My question :
Based on accepted answer here we should NEVER EVER compare strings with date. But in other side, a SYSDATE is allready a Date data type, and we should not compare It to a date - see here.
If I replace TO_DATE with TO_CHAR in upper SQL things go working again. But TO_CHAR function converts into String, so Oracle (I pressume) needs to convert this string again to date so you force Oracle to do an implicit data type conversion.
So, what should be a correct comparison with date and SYSDATE, in order to avoid Oracle working a bit slowly ?
You should not need to call either TO_DATE or TO_CHAR:
SELECT *
FROM my_table
WHERE date_column >= TRUNC(SYSDATE - 3) AND date_column < TRUNC(SYSDATE + 1);
Assuming date_column is a date type, you should be able to directly compare it against SYSDATE, or SYSDATE offset by some number of days.
I have a table with columns(year,day-month) -date type- in my database.
and a form with a text field for the user to enter a date.
how can I split the entered date to save it on db as following
year day_month
---- ---------
2018 03-04
I tried SUBSTR(TO_CHAR(TO_DATE(block.field)) in a trigger ,
but it didn't work bcz the column type is date, and I tried to add TO_DATE() as outer but the result was
year day_month
---------- ----------
03-04-2018 03-04-2018
How can I do it without changing my columns type?
I'd suggest you NOT to do that. Always store DATE values into DATE datatype columns. ALWAYS.
Later, if you want to present them differently, apply appropriate functions (such as TO_CHAR) to those values and display them any way you want.
In your example, that would be
TO_CHAR(date_column, 'yyyy') year
or
EXTRACT (year from date_column) year
and
TO_CHAR(date_column, 'dd-mm') day_month
[EDIT]
Once again (to repeat what I've said in a comment): the fact that you named columns in the database "year" (whose datatype is DATE) and "day_month" (whose datatype is also DATE) is completely useless.
Right now is (dd.mm.yyyy hh24:mi) 03.04.2018 10:32.
DATE datatype contains both date and time, so - how do you plan to put "2018" into the "year" column? What will you do with its month/day/hour/minutes/seconds component? It can't just "vanish", has to have some value. Is it the first of January at 00:00:00? Or what?
The same goes to your "day_month" column - it'll contain year, as well as hours/minutes/seconds, whether you want it or not.
Let's start with the "year": if you want to extract it from the Form item, that would be TO_CHAR, such as
to_char(:block.some_item, 'yyyy')
which results in a string, '2018'. You can't store it into a DATE datatype column, so you have to apply TO_DATE to it:
to_date(to_char(:block.some_item, 'yyyy'), 'yyyy')
and it will result in 01.04.2018 00:00:00 >>> see? Day, month, hours ... everything is here.
The alternative is to create those columns as VARCHAR2, but that's even worse.
Seriously, don't do that.
Try the following and make the necessary changes in Oracle Forms, substitute block and columns names instead of variables.
DECLARE
p_year VARCHAR2 (8);
p_date VARCHAR2 (8);
BEGIN
SELECT TO_CHAR (SYSDATE, 'YYYY') INTO p_year FROM DUAL;
SELECT TO_CHAR (SYSDATE, 'DD-MM') INTO p_date FROM DUAL;
DBMS_OUTPUT.put_line ('p_year --> ' || p_year || ' p_date --> ' || p_date);
END;
If your column is a DATE type, expect that it will require you to input a date data also.
In your case, you don't need to split a date. For the YEAR column, if the year value only matters to you, then you can use the TRUNC function
:BLK.YEAR_DATE_FIELD := TRUNC(:BLK.DATE_VALUE, 'YYYY');
and for the MONTH column, just save the date value there.
:BLK.MONTH_DATE_FIELD := :BLK.DATE_VALUE;
Also, maybe you just need to set the format mask of those two fields in Oracle forms. You can set the Format Mask of YEAR field to YYYY and MM-DD to the MONTH field.
The DATE data type is stored dates in tables as 7-bytes
byte 1 - century + 100
byte 2 - (year MOD 100 ) + 100
byte 3 - month
byte 4 - day
byte 5 - hour + 1
byte 6 - minute + 1
byte 7 - seconds+ 1
You CANNOT have a DATE data type that just stores year or month + day; it will always store all the components of the date/time.
So you either store the correct values in each column or you will have to make up values for the components you are not storing and will need to make sure that all the made up values are appropriate for the real values. It is just easier to use the real values in both columns.
So just do:
INSERT INTO your_table(
year,
day_month
) VALUES (
:BLK1.T_DATE,
:BLK1.T_DATE
);
Without splitting the date because a day_month without a year does not make sense (is 29th February a valid date? For the majority of years, no it isn't).
When you want to output it with a format then just format it as a string on output:
SELECT TO_CHAR( year, 'yyyy' ) AS year,
TO_CHAR( day_month, 'dd-mm' ) AS day_month
FROM your_table;
For eg I have a student table with a DOJ(date of joining) column with its type set as DATE now in that I have stored records in dd-mon-yy format.
I have an IN param at runtime with date passed as string and its in dd/mm/yyyy format. How do I compare and fetch results on date?
I want to fetch count of records of students who have DOJ of 25-AUG-92 per my database table student, but I am getting date as varchar in dd/mm/yyyy format in an IN param, kindly please guide.
I have tried multiple options such as trunc, to_date, to_char but, unfortunately nothing seems to work.
I have a student table with a DOJ(date of joining) column with its type set as DATE now in that I have stored records in dd-mon-yy format.
Not quite, the DATE data-type does not have a format; it is stored internally in tables as 7-bytes (year is 2 bytes and month, day, hour, minute and second are 1-byte each). The user interface you are using (i.e. SQL/PLUS, SQL Developer, Toad, etc.) will handle the formatting of a DATE from its binary format to a human readable format. In SQL/Plus (or SQL Developer) this format is based on the NLS_DATE_FORMAT session parameter.
If the DATE is input using only the day, month and year then the time component is (probably) going to be set to 00:00:00 (midnight).
I have an IN param at runtime with date passed as string or say varchar and its in dd/mm/yyyy format. How do I compare and fetch results on date.?
Assuming the time component for you DOJ column is always midnight then:
SELECT COUNT(*)
FROM students
WHERE doj = TO_DATE( your_param, 'dd/mm/yyyy' )
If it isn't always midnight then:
SELECT COUNT(*)
FROM students
WHERE TRUNC( doj ) = TO_DATE( your_param, 'dd/mm/yyyy' )
or:
SELECT COUNT(*)
FROM students
WHERE doj >= TO_DATE( your_param, 'dd/mm/yyyy' )
AND doj < TO_DATE( your_param, 'dd/mm/yyyy' ) + INTERVAL '1' DAY
The below should do what you've described. If not, provide more information on how "nothing seems to work".
-- Get the count of students with DOJ = 25-AUG-1992
SELECT COUNT(1)
FROM STUDENT
WHERE TRUNC(DOJ) = TO_DATE('25/AUG/1992','dd/mon/yyyy');
The above was pulled from this answer. You may want to look at the answer, because if performance is critical to you, there is a different way to write this query which doesn't use trunc, which will allow Oracle to use index on DOJ, if one is present.
Though I am bit late in posting this but I have been able to resolve this.
What I did was I converted both the dates to_char in similar formats and it worked here is my query condition that worked..
TO_CHAR(TO_DATE(C.DOB, 'DD-MON-YY'),'DD-MON-YY')=TO_CHAR(TO_DATE(P_Dob,'DD/MM/YYYY'),'DD-MON-YY'))
Thanks for the support all. :)
I was trying to select some data from my table using the following query:
select * from table1 where column1 = to_date('14-05-14','yy-mm-dd');
Where the column data type is DATE. I observed that, the above query won't return anything unless we modified it as,
select * from table1 where trunc(column1) = to_date('14-05-14','yy-mm-dd');
even though there are records available.
I checked the documentation for TRUNC.Can anyone please explain why this happens?
UPDATE
As per the valuable comments I think some time values may also associated with the DATE. But I cannot view/edit that time. How can I ensure there are time values associated.
Both TO_DATE and TRUNC are different. See the below example.
SQL> ALTER SESSION SET nls_date_format = 'dd/mm/yyyy hh24:mi:ss';
Session altered.
SQL> SELECT TO_DATE(SYSDATE) FROM DUAL;
TO_DATE(SYSDATE)
-------------------
28/05/2014 16:03:25
SQL> SELECT TRUNC(SYSDATE) FROM DUAL;
TRUNC(SYSDATE)
-------------------
28/05/2014 00:00:00
In Your first query to_date('14-05-14','yy-mm-dd') is comparing with the date field column1 in your table which has time values also. Whereas in Your 2nd query You are truncating the time part from table data and from Your query, that's why it's matching.
The DATE datatype stores the year (including the century), the month, the day, the hours, the minutes, and the seconds (after midnight).
TRUNC function will truncate the date to the day value, so that any hours, minutes, or seconds will be truncated off.
For more info please look at these below links
http://docs.oracle.com/cd/B28359_01/server.111/b28318/datatype.htm#CNCPT413
http://www.techonthenet.com/oracle/functions/trunc_date.php