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_23799417_1 ( production_code VARCHAR, directed_by VARCHAR )

### Question ###
What is the production code directed by Matt Shakman?

### Accurate SQL ###

SELECT production_code FROM table_23799417_1 WHERE directed_by = "Matt Shakman"