How to fetch the date from epoch in CockroachDB - cockroachdb

I have a column which has the time stamp stored in epoch. I need to fetch the date from the epoch time stamp. For instance for epoch = 1552942715, I need to fetch the date as 1552867200. How can this be achieved?

create table test (epoch text NULL);
Create table sample where the column is text datatype.
select (epoch::int)::TIMESTAMPTZ from test;
If the column is of type int or any other number then just cast it to timestampz

Related

Fetch Hours from Created date

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.

How to write date / timestamp string to Date timestamp column in Oracle DB?

I have stored some Oracle tables in Hadoop using AVRO file format and Hive external tables to access the data.
I have stored Date and Timestamp values as a formatted String, using the TO_CHAR function from Oracle on the import.
Now I want to export this exact data back with Spark to an Oracle table having a Date column. I use the command:
// Create a data frame from the Hive table
val data = sqlContext.sql("select * from avro_table")
// export df to existing oracle table
data.write.mode("overwrite").jdbc(jdbcString, "tableName", prop)
But then i get the error:
ORA-00902: invalid data type
This is because it tries to insert a string into a date column. Is there a safe way to insert a date / timestamp string from a Spark dataframe to an Oracle date / timestamp column? With safe i mean do not lose any timezone information.
You should use to_date, to_timestamp and/or date_format functions to do the transformation from stringified date/timestamp values to their corresponding type-aware ones.
date_format(dateExpr: Column, format: String): Column Converts a date/timestamp/string to a value of string in the format specified by the date format given by the second argument.
to_date(e: Column, fmt: String): Column Converts the column into a DateType with a specified format (see http://docs.oracle.com/javase/tutorial/i18n/format/simpleDateFormat.html) return null if fail.
to_timestamp(s: Column, fmt: String): Column Convert time string to a Unix timestamp (in seconds) with a specified format (see http://docs.oracle.com/javase/tutorial/i18n/format/simpleDateFormat.html) to Unix timestamp (in seconds), return null if fail.
Use select or withColumn operators.
A sample code could be as follows:
data.withColumn("real_date", date_format(...))
.write
.mode("overwrite")
.jdbc(jdbcString, "tableName", prop)

Timestamp to complete date format

We are working on oracle 11g enterprises edition. We are facing issue in getting value of date for type TIMESTAMPTZ and TIMESTAMPLTZ. We are storing those dates into one csv file using apache metamodel. We are fetching date from database using :
TIMESTAMPLTZ columnValue = (TIMESTAMPLTZ) row.getValues()[pos];
Timestamp timestamp=columnValue.timestampValue(connection,Calendar.getInstance(Locale.getDefault()));
Date dateByTimeStamp=new Date(timestamp.getTime());
Date dateByDateValue = columnValue.dateValue(connection);
String formattedDate = new SimpleDateFormat("dd-MMM-yy hh.mm.ss.SSSSSS a").format(dateByTimeStamp or dateByDateValue );
dateByDateValue contains date upto yyyy-mm-dd hh:mm:ss format. eg. 2016-10-12 08:49:30. There is no way to get value of nanoseconds and time zone using this object.
dateByTimeStamp object contains cdate that have value of date upto nanoseconds and also have time zone. But the value of date time differ because of time zone, but this cdate object contains information regarding nanoseconds precision.
Is there any way to get date in complete format so that the formatted date can directly be used to restore into another oracle db?

Which Data types are correct for storing numeric year input and numeric month in Oracle?

I am learning oracle 11g. I need to create columns to store Year and Month in the following sample format:
Year: 2015
Month: 6
I saw Date Time data type which takes whole date only .Also Number type may allow invalid year and month. But I want them in the given form while avoiding invalid month and year. Please tell me how to fix it.thanks
Updates: is this okay for such inputs?
CREATE TABLE FOOBAR (YYYY DATE, MM DATE);
The best solution is to store dates in DATE columns. Oracle has some pretty neat date functions, and you'll find it easy to work with storing the first of the month in a single DATE column. Otherwise you'll find yourself constantly extracting elements from other dates or cluttering your code with TO_CHAR() and TO_DATE() calls. Find out more.
However, if you have a rigid requirement, you can use strong typing and check constraints to avoid invalid months:
CREATE TABLE FOOBAR (
YYYY number(4,0) not null
, MM number(2,0) not null
, constraint foobar_yyyy_ck check (yyyy != 0)
, constraint foobar_mm_ck check (mm between 1 and 12)
);
This won't do what you want because it will default the missing elements:
CREATE TABLE FOOBAR (YYYY DATE, MM DATE);
We can't store just a year or just a month in DATE columns.
Use the DATE data type..
and when perform insert operation onto your db.. use
TO_DATE ('November 13, 1992', 'MONTH DD, YYYY')
For input and output of dates, the standard Oracle date format is DD-MON-YY, as follows:
'13-NOV-92'
perform insert operation/query like this:
INSERT INTO table_name (name, created_at) VALUES
('ANDY', TO_DATE ('November 13, 1992', 'MONTH DD, YYYY'));
Here is link to the guide as well:
https://docs.oracle.com/cd/B28359_01/server.111/b28318/datatype.htm#i1847
If you want to store month and year separately in the db you may use NUMBER & NUMBER(n)
https://docs.oracle.com/cd/B28359_01/server.111/b28318/datatype.htm#i22289
Hope this helps..

How can I convert a date to another format at run time in Oracle?

I have a date string coming from user input in the format of DD/MM/YYYY and I need to match it against a date column in our database in the format of DD-MON-YY.
Example input is 01/01/2015 and example date column in our database:
SELECT MAX(creation_date) FROM orders;
MAX(creation_date)
------------------
06-AUG-15
I need to query in the format:
SELECT * FROM orders WHERE creation_date = 01/01/2015
and somehow have that converted to 01-JAN-15.
Is it possible with some built-in Oracle function?
Use to_date, if the column in the table is in date format
http://www.techonthenet.com/oracle/functions/to_date.php
to_char allows you to specify different formats in a SQL statement.
Example: to_char(sysdate,'DD-MON-YYYY') will display 06-AUG-2015 for today's date.
TO_CHAR
Use to_date to compare your date column to a date string, but be careful in doing so since your date column may include a time component that isn't showing when selecting from your table.
If there is no index on your date column, you can truncate it during the comparison:
SELECT * FROM orders WHERE TRUNC(creation_date) = TO_DATE('01/01/2015','mm/dd/yyyy');
If there is an index on your date column and you still want to use it then use a ranged comparison:
SELECT * FROM orders
WHERE creation_date >= TO_DATE('01/01/2015','mm/dd/yyyy')
and creation_date < TO_DATE('01/01/2015','mm/dd/yyyy')+1;

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