HiRDB database supports SUM function without over clause. SQLWays leaves it as is.

Oracle:

select  sum([DISTINCT|ALL] a); 

HiRDB:

SET n= sum([DISTINCT|ALL] a); 

HiRDB hasn't equivalent for SUM function with over clause. SQLWays leaves it as is and adds message /*Сould not convert 'sum'*/.

Oracle:

n:= sum([DISTINCT|ALL] a) over (partition by b);   

HiRDB:

SET n= sum([DISTINCT|ALL] a) over (partition by b);
/*Сould not convert 'sum'*/