So you spotted that? I have no proof or links to share, but I've always thought SQL was inspired by, or at least made to not look out of place next to COBOL. I recall COBOL coding card layout interpreted a flag on punch cards at the char column where top-level picture clauses needed to start specifically for designating a line as SQL for static embedded SQL preprocessing.
I think it’s more that computers at the time didn’t all have lowercase characters. Consider that even C and C++ supported trigraph/digraph compatibility chars until something like last year (and IBM still complained…):
C is much older than Unicode, so it's not that surprising that some systems are still using https://en.wikipedia.org/wiki/ISO/IEC_646 and replacing some reserved punctuation (e.g., curly braces) with their country's accented letters.
