Database: chicago_crime
Question: How many of the crimes that happened in the street have FBI title "Homicide 1st & 2nd Degree"?
SQL: SELECT SUM(CASE WHEN T2.location_description = 'STREET' THEN 1 ELSE 0 END) FROM FBI_Code AS T1 INNER JOIN Crime AS T2 ON T2.fbi_code_no = T1.fbi_code_no WHERE T1.title = 'Homicide 1st & 2nd Degree'