11.4.10. HQL Standardized Functions

The following functions are available in HQL regardless of the underlying database in use.

Table 11.10. HQL Standardized Funtions

Function Description
BIT_LENGTH
Returns the length of binary data.
CAST
Performs a SQL cast. The cast target should name the Hibernate mapping type to use. See the chapter on data types for more information.
EXTRACT
Performs a SQL extraction on datetime values. An extraction extracts parts of the datetime (the year, for example). See the abbreviated forms below.
SECOND
Abbreviated extract form for extracting the second.
MINUTE
Abbreviated extract form for extracting the minute.
HOUR
Abbreviated extract form for extracting the hour.
DAY
Abbreviated extract form for extracting the day.
MONTH
Abbreviated extract form for extracting the month.
YEAR
Abbreviated extract form for extracting the year.
STR
Abbreviated form for casting a value as character data.
Application developers can also supply their own set of functions. This would usually represent either custom SQL functions or aliases for snippets of SQL. Such function declarations are made by using the addSqlFunction method of org.hibernate.cfg.Configuration