Hi, Consider the following table: create table "table1" ("Pdate" timestamp, "Price" double); insert into "table1" values ('2007-04-21 00:00:00.000000', 7555); insert into "table1" values ('2007-04-22 00:00:00.000000', 7834); insert into "table1" values ('2007-04-23 00:00:00.000000', 5631); insert into "table1" values ('2007-04-24 00:00:00.000000', 7555); insert into "table1" values ('2007-04-25 00:00:00.000000', 7555); I tried using the following query: SELECT ("table1"."Pdate") AS "PurchaseaDate", ("table1"."Pdate" + interval '1' month) AS "PurchaseaDate2", ("table1"."Price") AS "Price" FROM "table1" And got the error: !TypeException:user.s6_2[19]:'mtime.addmonths' undefined in: _61:any := mtime.addmonths(_59:timestamp, A0:int) !TypeException:user.s6_2[20]:'bat.insert' undefined in: _62:any := bat.insert(_53:bat[:oid,:timestamp], _58:oid, _61:any) Any ideas? Thanks, Alfred. -- View this message in context: http://www.nabble.com/Adding-interval-month-problem-tp22657190p22657190.html Sent from the monetdb-users mailing list archive at Nabble.com.