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_21666472_1 (no_in_series VARCHAR, written_by VARCHAR)

### Question ###
How many number in series's are written by Greg Haddrick?

### Accurate SQL ###

SELECT COUNT(no_in_series) FROM table_21666472_1 WHERE written_by = "Greg Haddrick"