I want to perform data time operations using hibernate HQL.
I want to add and subtract two dates as well as I want to subtract 1 year or 1 month from a particular date.
How is this possible using HQL in hibernate?
I want to perform data time operations using hibernate HQL.
I want to add and subtract two dates as well as I want to subtract 1 year or 1 month from a particular date.
How is this possible using HQL in hibernate?
See Performing Date/Time Math In HQL? for an example.
To use custom sql you must wrote an own hibernate dialect and register:
registerFunction("weekday",
new SQLFunctionTemplate(Hibernate.INTEGER, "to_char(?1,'D')") );
You need to create your own dialect. Something like the following:
public class MyDialect extends MySQLInnoDBDialect{
public MyDialect() {
super();
registerFunction("date_add_interval", new SQLFunctionTemplate(Hibernate.DATE, "date_add(?1, INTERVAL ?2 ?3)"));
}
}
See Performing Date/Time Math In HQL? for an example.
To use custom sql you must wrote an own hibernate dialect and register:
registerFunction("weekday",
new SQLFunctionTemplate(Hibernate.INTEGER, "to_char(?1,'D')") );
This is an open issue in Hibernate. As of Hibernate 3.3 there is no standard way to handle date comparisons purely in HQL:
https://hibernate.atlassian.net/browse/HHH-2434
Hibernate 4.3 offers functions to access Date/Time in HQL which are:
current_timestamp() , current_date() , current_time()
Arithmetic operations can be managed by:
SECOND(...) , MINUTE(...) , HOUR(...) , DAY(...) , MONTH(...) , YEAR(...)
In Hibernate/MySQL (at least) You can convert to and from a Unix Timestamp. Since the unix timestamp is an integer you can add an integer number of seconds to it.
FROM_UNIXTIME(UNIX_TIMESTAMP(date)+ (allowedTimeWindow*86400)) as deadline
It has limitations but it's a lot easier than the approaches above.
Disclaimer: I am a Java novice
I was able to use current_date() >= fromDate AND dateadd(day, -1, getdate()) <= toDate
in an HQL statement against a Sybase db in Hibernate 3.5.3, without registering any functions.
The Hibernate issue Fred Haslam has referenced has been solved. With Hibernate 6.0+ versions, you can add Temporal Unit
operations to date fields as simple as this:
Select m From MyObject m Where m.dateField + 10 MONTH - 5 DAY < current_date
*current_date
being a Hibernate constant for current date.
Usage sample of approach with dialect for JPA + Hibernate 4.3.1 + MySQL 5
public class SampleMySQL5InnoDBDialect extends org.hibernate.dialect.MySQL5InnoDBDialect {
public SampleMySQL5InnoDBDialect() {
super();
registerFunction("date_sub_days", new SQLFunctionTemplate(StandardBasicTypes.DATE, "date_sub(?1, interval ?2 day)"));
}
then for your class with mapping annotation:
@NamedQuery(name = "SampleEntity.getSampleEntitiesForGapOverlapCalculations", query = "from SampleEntity as se where "
+ "((se.toDate between :startDate and :endDate) or (date_sub_days(se.toDate, se.duration) between :startDate and :endDate)) order by se.toDate asc, se.duration desc")
SampleEntity has toDate field of type java.sql.Date and duration integer field (duration in days) and we are calculating fromDate = toDate - duration and selecting all entities which have fromDate or toDate inside interval [startDate, endDate].
Hibernate4.3 provides native functions to access Dates/Timestamps and to perform arithmatic operations on them
Here is the link to the documentation of what expressions can be used in HQL. Few of which i am mentioning: To access date/time:
current_date(), current_time(), and current_timestamp()
Arithmetic operations can be done by following. These functions take Time as input:
second(...), minute(...), hour(...), day(...), month(...), and year(...)
One can get absolute difference of in HQL by
current_timestamp() - dateInstance
where dateInstance can have definition
@Column(name = "updated_at")
@Temporal(TemporalType.TIMESTAMP)
private java.util.Date updatedAt;
The result is in 0.1 seconds. So for a absolute difference of 1 second, the above expression will give result as 10.
So a query would look like :
select t from Table t where (current_timestamp() - updatedAt)>600
Postgres users...
registerFunction("dateadd", new SQLFunctionTemplate(StandardBasicTypes.DATE, "(?1 + INTERVAL ?2)"));
with SQL usage like:
now() < dateadd(:mydate, '-1 day')
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