How to format date in Hibernate HQL?

hi,

I am using Hibernate in my Spring Java app and I have an object Event with a field eventDate of type Date.

What are my options for formatting a date to a string using the YYYY-MM-DD format? I guess I could retrieve the field as a date, and then format the date in Java, but that's probably not too efficient.

My app is currently setup to work with a MySQL database, but I would also like it to work on Postgresql.

thanks in advance!

 

You can use the following that converts a date to a string with the specified format:

to_char(mydate,'yyyy-mm-dd')

 

mysql:

SELECT id, name, DATE_FORMAT(eventDate, '%Y-%m-%d') AS formattedEventDate FROM Event;

postgres sql:

SELECT id, name, TO_CHAR(eventDate, 'YYYY-MM-DD') AS formattedEventDate FROM Event;

java:

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
String formattedDate = sdf.format(event.getEventDate());

 

SELECT e, DATE_FORMAT(e.eventDate, '%Y-%m-%d') AS formattedDate FROM Event e

DATE_FORMAT is the function for MySQL. Replace it with to_char(e.eventDate, 'YYYY-MM-DD') for Postgresql. This method retrieves the Event object (e) and creates a new alias formattedDate with the formatted date string.

 

One option is to use the DATE_FORMAT function provided by MySQL and to_char function provided by Postgresql in your Hibernate query to format the date directly in the database query. This will retrieve the date in the desired format, decreasing the need to format it in Java.

For MySQL:

SELECT DATE_FORMAT(eventDate, '%Y-%m-%d') FROM Event;

Code (markup):

For Postgresql:

SELECT to_char(eventDate, 'YYYY-MM-DD') FROM Event;

Code (markup):

Alternatively, you can use the @Temporal annotation in Hibernate to specify the date format in your Event entity class:

@Temporal(TemporalType.DATE)
@Column(name = "eventDate")
private Date eventDate;

Code (markup):

Then, when you retrieve the eventDate from the Event object, you can use a SimpleDateFormat to format it as a string in the desired format:

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
String formattedDate = sdf.format(event.getEventDate());

Code (markup):

Both options should allow you to efficiently format the date to the desired string format without impacting performance.