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_28520 ( "No. in series" real, "No. in season" real, "Title" text, "Directed by" text, "Written by" text, "Original air date" text, "Production code" text, "U.S. viewers (million)" text )

### Question ###
which production codes were written by andrew goldberg

### Accurate SQL ###

SELECT "Production code" FROM table_28520 WHERE "Written by" = 'Andrew Goldberg'