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_25851971_1 ( production_code VARCHAR, written_by VARCHAR )

### Question ###
What was the production code of the episode written by Anthony Sparks?

### Accurate SQL ###

SELECT production_code FROM table_25851971_1 WHERE written_by = "Anthony Sparks"