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_29747178_2 ( series__number VARCHAR, directed_by VARCHAR )

### Question ###
What is the series # when the director is john showalter?

### Accurate SQL ###

SELECT series__number FROM table_29747178_2 WHERE directed_by = "John Showalter"