mysql - SQL: get unique rows based on concatenation of two columns -

i need sql statement derive list of rows unique based on concatenation of 2 columns.

given set of data, want result remove duplicate rows duplicate defined concatenation of column1 , column2.

things:

id    column1    column2        column3 1                 z              l 2        b          y              g 3        b          y              g 4                 y              h 5                 z              l 

this came with:

select distinct ( column1 || column2 ) things 

result:

az ay 

this works fine, derives list of unique concatenation of column1 , column2,

i need column3 returned well, in:

column1    column2    column3             z            l     b         y            g                y            h 

this not work:

select distinct ( column1 || column2 ), column3 things 

as returns more rows needed.

how construct sql statement derive desired result of unique rows based on concatenation of 2 columns? not matter if column3 not unique.

if not care values of column3 how come, can use group by

select  column1, column2, column3 things group column1,column2