Increment an integer

You already answered the question yourself, but to make things a bit clearer:

variable + 1 

is an arithmetic expression - add 1 to the value of the variable.

variable+1

is an offset operation on a character variable. For example, if variable contains ABC, variable+1 is BC.

This can be especially confusing when dealing with NUMCs. For example, with variable = '4711', variable + 1 is evaluated to 4712, whereas variable+1 is '711' (a character sequence).

The error you saw occurred because it's not possible to perform the index operation on a non-character-like variable.

You mean like:

ADD 1 to lv_id.

By the way, when you loop over an internal table, SY-TABIX has the loop counter.

Uh, I got it. It's the f****** spaces...

lv_id = lv_id + 1

works...