In the interest of correctness:
The 'More information about this error' goes to:
https://docs.moodle.org/19/en/error/moodle/ddltablealreadyexists
which contains no info.
IF using the dropdown menu on link above, doesn't show any but 'supported' versions.
One has to know to change the number of version in the URL, thusly:
https://docs.moodle.org/22/en/error/moodle/ddltablealreadyexists
which also begets nada/zip/nothing.
Drop down menu there shows a different list ... 2.2 docs -> 2.7, 2.9, 3.0 and 3.1 docs (skips 2.8).
So for this particular issue ... no information seems to be available to point the op to in efforts to help the op find a solution - which is what these forums are supposed to be about! ;)
'spirit of sharing', Ken