mysql - Can't CONCAT within query containing GROUP BY -

i have following query (irrelevant parts omitted):

           select date_format(calc_dt, '%y-%m-%dt%tz') formatted_calc_dt,                   concat(date_format(calc_dt, '%y-%m-%dt%tz'), '')              calc_calculation_results          group formatted_calc_dt 

error code: 1055. expression #2 of select list not in group clause , contains nonaggregated column 'my_database_name.calc_calculation_results.calc_dt' not functionally dependent on columns in group clause; incompatible sql_mode=only_full_group_by

the challenge is:

• i need concat formatted calc_dt other stuff
• i need create view out of query, can't use subqueries

the point of grouping, if helps, group dates hour.

is there way can want?

i think missing key word 'as' in query in 2 places.

try this,

select date_format(calc_dt, '%y-%m-%dt%tz') formatted_calc_dt, concat(date_format(calc_dt, '%y-%m-%dt%tz'), '') other_concat calc_calculation_results group formatted_calc_dt 

old part 1:

select date_format(calc_dt, '%y-%m-%dt%tz') formatted_calc_dt, 

new part 1:

select date_format(calc_dt, '%y-%m-%dt%tz') formatted_calc_dt, 

old part 2:

concat(date_format(calc_dt, '%y-%m-%dt%tz'), '') calc_calculation_results group formatted_calc_dt 

new part 2:

concat(date_format(calc_dt, '%y-%m-%dt%tz'), '') other_concat  calc_calculation_results group formatted_calc_dt