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_1137718_2 (fastest_lap VARCHAR, grand_prix VARCHAR)

### Question ###
What was the fastest lap at the Mexican Grand Prix?

### Accurate SQL ###

SELECT fastest_lap FROM table_1137718_2 WHERE grand_prix = "Mexican grand_prix"