John,

<< Indeed.  As I understand it this is a restriction on parameters being
used as result columns (or column modifiers), not anything to do with
Intervals as such. >>

You are correct.  You simply can't use parameters in the SELECT expressions
list.

Tim Young
Elevate Software
www.elevatesoft.com

Uli,

<< You cannot use parameters in intervals. >>

Not correct.  John's example will work fine for Sorin:

SELECT datefield+CAST(integerfield AS INTERVAL MONTH) AS NewDateField FROM
Table

You can cast any INTEGER as an INTERVAL.

Table and rows:

CREATE TABLE "MonthTest"
(
"DateField" DATE,
"IntegerField" INTEGER
)!

INSERT INTO "MonthTest" VALUES (DATE '2012-06-20', 10)!

INSERT INTO "MonthTest" VALUES (DATE '2012-06-20', 2)!

INSERT INTO "MonthTest" VALUES (DATE '2012-06-20', 3)!

INSERT INTO "MonthTest" VALUES (DATE '2012-06-20', 4)!

Tim Young
Elevate Software
www.elevatesoft.com