I use MySql and I have table like this

```none
id |city               | address         | work_time
-------------------------------
1  |London - center    |London street 1  |7am - 10 pm
2  |London - center 2  |London street 2  |7am - 10 pm
3  |London - center 3  |London street 3  |7am - 10 pm
4  |Paris - bol 1      |Bol street 3     |9am - 10 pm
5  |Paris - bol 2      |Bol street 13    |9am - 10 pm

```

How to group all cities by first string before `-` and to crop all letters after this symbol? 
I want to show in list only London and Paris like that

```none
  id |city               
  -------------------------------
  1  |London 
  2  |Paris 

```