Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_15 ( year INTEGER, issue_price VARCHAR, mintage VARCHAR )

### Question ###
What is the Year of the Coin with an Issue Price of $1089.95 and Mintage less than 900?

### Accurate SQL ###

SELECT SUM(year) FROM table_name_15 WHERE issue_price = "$1089.95" AND mintage < 900