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_15621965_18 ( no VARCHAR, position VARCHAR, school_club_team VARCHAR )

### Question ###
WHAT WAS THE JERSEY NUMBER OF THE ROSTER PLAYER FROM OKLAHOMA STATE WHO PLAYED GUARD?

### Accurate SQL ###

SELECT no FROM table_15621965_18 WHERE position = "Guard" AND school_club_team = "Oklahoma State"