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_name_57 ( maximum_diameter VARCHAR, name__year_commissioned_ VARCHAR )

### Question ###
What is the maximum diameter of the Mid West Gas Pipeline (1999)?

### Accurate SQL ###

SELECT maximum_diameter FROM table_name_57 WHERE name__year_commissioned_ = "mid west gas pipeline (1999)"