Note: SQL DISTINCT is available only in MS SQL not MySQL
Select Distinct * from table
removed duplicates rows not duplicate column. DISTINCT works on rows not column. If you join two tables lets say
Doctors Appointment (Patients)
doc_id | Doc_Name Patient Name, doc_id
If you left join on doc_id, it will produce a table with doctor name repeated more than once for each appointment he has. Using distinct will not solve the problem because the rows are already distinct different (Each doctor had a different appointment) so in each row the patient name is different in front of the same doctor.