hi, there. i'm trying to write a SQL statement which does the following things.
1. checks if data already exists in the database 2. if not, insert data into database otherwise skip. for example, i'd like to insert a student called 'Michael Jordan' whose ID is 'JORDANMICHAEL' only if the id, 'JORDANMICHAEL' does not already exist in the database. anyway, my query looks like... insert into student (studentid, fname, lname) select 'JORDANMICHAEL', 'Michale', 'Jordan' from student where studentid not in (select studentid from student); however, this does not seem to work. it does not insert data even if it does not exist in the database. hmm! any clue? thanks. ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match