How to improve SQL Teradata with OVER PARTITION BY

I have a query with more than 7 columns with some counts() and sum() values, I was very slow, then I was trying using OVER PARTITION BY , but in the result table I have a error "Selected non-aggregate values must be part of the associated group".

This is the query :

insert into SQUEMA.TABLE_Bselect SUBSTR(cast(date as char(6)) ,1,4) ||'-'|| SUBSTR(cast(date as char(6)) ,5,6) as date ,column1,column2,column3,....column7,count(column8) OVER (PARTITION BY date, column1,...,column7) as column8SUM(column9) OVER(ORDER BY date ) as column9from SQUEMA.TABLE_A tb where tb.date between '201711' and '201812'group by date, column1,...,column7;

Error

Selected non-aggregate values must be part of the associated group