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Use java.lang Methods as Functions with SQL-J

Use java.lang Methods as Functions with SQL-J

You can use methods of java.lang classes for all of the functions found built-in to other databases. For example, you can call the static method java.lang.Math.abs, which is similar to ABS in other database systems. You can call the method this way:

 SELECT (CLASS java.lang.Math).abs(balance) FROM account 

You can also define an alias for any static Java method, making it appear as a native built-in function. You use the CREATE METHOD ALIAS statement. Alias definitions are specific to a database; to use an alias when connected to a database, you must define the alias within that database. Once the aliases are defined, they are available to all connections.

 CREATE METHOD ALIAS ABS FOR java.lang.Math.abs 

After defining the alias, you can call the method this way:

 SELECT ABS(balance) FROM account

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