Date Functions in Hive

Introduction to Date Functions in Hive

Hive provides Date Functions that help us in performing different operations on date and date data types. Hive has a wide variety of built-in date functions similar. Date functions in Hive are almost like date functions in RDBMS SQL. Date functions are used for processing and manipulating data types. In this article, we will discuss various Date Functions provided by Hive in detail with multiple examples.

Syntax

Data Types in Hive are very complicated and highly formatted too. Every date value holds multiple information like a second, minute, hour, day, week, month, year, century, etc., all these date data can be manipulated using Hive built-in date functions.

• current_date(): This function returns the current system date alone. It does not include the time part.
• current_timestamp(): This function returns the current system time and date in a complete format.
• unix_timestamp(): This function uses the default time zone of the Unix epoch and returns a converted time format of the number of seconds between the Unix epoch and the specified date in string format.
• unix_timestamp(str date): This function is used to convert  ‘yyyy-MM-dd HH:mm: ss’ date format into normal Unix timestamp. It returns a converted time format of the number of seconds between the Unix epoch and the specified date in string format. And, it returns 0 on failure.
• unix_timestamp(str date, str pattern): This function is used to convert normal data type into another data type which can be specified in string pattern. It returns a converted time format of the number of seconds between the Unix epoch and the specified date in string format. And, it returns 0 on failure.
• from_unixtime(bigint number of seconds  [, str format]): This function, from Unix epoch, converts the given number of seconds and returns the date in ‘yyyy-MM-dd HH:mm: ss’ format.
• from_utc_timestamp(str date, time zone): This function converts the specified date format in string format to the specified time zone in the second part of the expression. This function is used for the time zone conversion of the UTC time zone to another time zone.
• to_utc_timestamp(str date, time zone): This function converts the specified data format in a string format in the time zone specified in the second part to the UTC time zone. This function is used for the time zone conversion of another time zone to the UTC time zone.
• to_date(str timestamp): This function is used to return only the date part of the specified timestamp in standard date format ‘yyyy-MM-dd’.
• date_add(str date, int number of days): This function is used to add the specified number of days to the given date and return the final added date.
• date_sub(str date, int number of days): This function is used to subtract the specified number of days from the given date and return the final subtracted date.
• date_diff(str date 1, str date 2): This function is used to find the difference between two specified dates and returns the difference in the number of days.
• Year (str date): This function is used to return the year portion of the given date in string format.
• Quarter (str date): This function is used to return the year portion of the given date in string format.
• Month (str date): This function is used to return the month portion of the given date in string format.
• Day (str date): This function is used to return the day portion of the given date in string format.
• dayofmonth (timestamp or date or string): This function is used to return the quarter number of the given date in string format.
• Hour (str date): This function is used to return the given date’s hour portion in string format.
• Minute (str date): This function is used to return the minute portion of the given date in string format.
• Second (str date): This function is used to return the second portion of the given date in string format.
• weekofyear(str date): This function is used to return the week number of the given date in string format.
• trunc(timestamp, str unit): This function is used to strip off all the given timestamp fields in string format.
• last_day(str date): This function is used to return the last day of the specified month in the given date in string format.
• next_day(str start date, str day of the week): This function is used to return the next day of the week from the given start date.
• months_between(str date 1, str date 2): This function returns the number of months between the given dates.
• date_format(timestamp or date or string, str format): This function is used to convert the specified date in any specified to the given format.

How Does Date Function work in Hive?

• Hive does not have date data types.
• Dates in Hive are considered as normal strings.
• Hive provides this wide variety of Date Functions for working, manipulating, and processing of date data types as per the requirements.
• Date data type handling in Hive is more difficult as compared to RDBMS.
• Hive is not able to throw an effective error when dealing with improper date formats.
• Any format incompatible date formats will result in NULL as output instead of throwing an error in Hive.
• date_format function can be used to convert any format to the required date format.

Examples to Implement in Date Functions

Below we will learn about the examples to implement in date function:

1. current_date()

Code:

select current_date();

Output:

2. current_timestamp()

Code:

select current_timestamp();

Output:

3. unix_timestamp(str date)

Code:

select unix_timestamp('2000-01-01 00:00:00');

Output:

4. unix_timestamp(str date, str pattern)

Code:

select unix_timestamp('2009-03-20 00:00:00', 'yyyy-MM-dd');

Output:

5. from_unixtime(bigint number of seconds  [, str format])

Code:

select from_unixtime(unix_timestamp());

Output:

6. from_utc_timestamp(str date, time zone)

Code:

select from_utc_timestamp('1990-01-01 09:00:00', 'JST');

Output:

7. to_utc_timestamp(str date, time zone)

Code:

select to_utc_timestamp ('1990-02-13 00:00:00','America/Denver');

Output:

8. to_date(str timestamp)

Code:

select to_date ('1990-02-13 07:57:33');

Output:

9. date_add(str date, int number of days)

Code:

select date_add ('2020-02-23', 4);

Output:

10. date_sub(str date, int number of days)

Code:

select date_sub ('2020-02-23', 4);

Output:

11. date_diff(str date 1, str date 2)

Code:

select date_add ('2020-02-23', 2020-02-19);

Output:

12. year(str date)

Code:

select year ('2020-02-23 05:23:36');

Output:

13. quarter(str date)

Code:

select quarter ('2020-02-23 05:23:36');

Output:

14. month(str date)

Code:

select month ('2020-02-23 05:23:36');

Output:

15. day(str date)

Code:

Select day('2020-02-23 05:23:36');

Output:

16. dayofmonth(timestamp or date or string)

Code:

select dayofmonth ('2020-02-23 05:23:36');

Output:

17. hour(str date)

Code:

select hour ('2020-02-23 05:23:36');

Output:

18. minute(str date)

Code:

select minute ('2020-02-23 05:23:36');

Output:

19. second(str date)

Code:

select second ('2020-02-23 05:23:36');

Output:

20. weekofyear(str date)

Code:

select weekofyear ('2020-01-23 05:23:36');

Output:

21. months_between(str date 1, str date 2)

Code:

select months_between ('2020-01-20’, ‘2019-10-15’);

Output:

Recommended Articles

This is a guide to Date Functions in Hive. Here we discuss syntax, how does the date function in hive work with examples to implement with proper codes and outputs. You can also go through our other related articles to learn more –

1. Views in Hive
2. Bucketing in Hive
3. Hive Data Types
4. Hive String Functions
5. Guide to PostgreSQL Date Functions