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_dev_28 ( "id" int, "gender" string, "systolic_blood_pressure_sbp" int, "consent" bool, "hemoglobin_a1c_hba1c" float, "hematocrit_hct" float, "fasting_triglycerides" int, "fasting_blood_glucose_fbg" float, "diastolic_blood_pressure_dbp" int, "hba1c" float, "metformin" bool, "age" float, "NOUSE" float )

### Question ###
hba1c at screening 6.5 % to 9 % for patients on metformin

### Accurate SQL ###

SELECT * FROM table_dev_28 WHERE hba1c > 6.5 AND hemoglobin_a1c_hba1c < 9 AND metformin = 1