DATE_ADD function Error

Summary:

Hi Everyone!

I am try to add specific year to the hire date using Date_add function, but it is throwing "Missing right parenthesis error". Could any one help me what i am missing here?

Query used:

SELECT  DATE_ADD(ppos.DATE_START, INTERVAL 60 YEAR) AS RTM, 

papf.person_number

FROM per_periods_of_service ppos, 

per_all_people_f papf

where 

1=1

and ppos.person_id = papf.person_id

Error Thrown:

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):