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_72087 ( "No. in set" real, "No. in series" real, "Title" text, "Directed by" text, "Written by" text, "Original air date" text, "Production code" text )

### Question ###
What is the episode number that has production code 8abx15?

### Accurate SQL ###

SELECT MIN("No. in series") FROM table_72087 WHERE "Production code" = '8ABX15'