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12.4.10. HQL Standardized Functions
The following functions are available in HQL regardless of the underlying database in use.
| 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
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