Select records only if previous row coloumn is different SQL in MYSQL

Question

I have a problem with MySql, that I can't find if is possible to solve with MySql.

I have this table for example:

|cod | value    |
| 1  |  value1  |
| 1  |  value2  |
| 2  |  value3  |
| 1  |  value4  |
| 5  |  value5  |
| 5  |  value6  |
| 2  |  value7  |

The result that I would like:

|cod | value    |
| 1  |  value1  |
| 2  |  value3  |
| 1  |  value4  |
| 5  |  value5  |
| 2  |  value7  |

So get row only if it is has cod different from previous record.

So my question is: Is possibile doing this with Mysql? Is there any way for know the previous row value in MySQL?

Answer 1

I'have solved in this way, but I don't know if it is the best way:

set @last := 'NULL';
Select cod, test.value, @last := cod as previous
from test
where @last != cod

Some one more skilled in SQL could suggest me if it is a valid method?