oracle - SQL identifying changes in chronological order -

i use sql

i have table row every user every day

uid date       attribute 123 2017-01-01 awesome 123 2017-01-02 awesome 123 2017-01-03 awesome 123 2017-01-04 not awesome 123 2017-01-05 awesome 123 2017-01-06 awesome 123 2017-01-07 awesome 166 2017-01-01 kinda awesome 166 2017-01-02 awesome 166 2017-01-03 awesome 166 2017-01-04 awesome 166 2017-01-05 awesome 166 2017-01-06 awesome 166 2017-01-07 awesome 

i want write sql query allow me identify date attribute changes user, user's previous attribute, , user's new attribute.

i don't know start.

you can use window function lag check if current row value matches last row function:

select * (     select t.*,         case              when attribute <> lag(attribute, 1, attribute) on (                     partition uid_ order date_                     )                 1             else 0             end flag     your_table t     ) t flag = 1; 

demo

please try not use reserved keywords such uid, date identifiers (i've added underscore _ them in solution).