Convert latin1 characters on a UTF8 table into UTF8
After I searched about an hour or two for this answer, I needed to migrate an old tt_news db from typo into a new typo3 version. I tried to convert the charset in the export file and import it back already, but didn't get it working.
Then I tried the answer above from ABS and started an update on the table:
UPDATE tt_news SET
title=convert(cast(convert(title using latin1) as binary) using utf8),
short=convert(cast(convert(short using latin1) as binary) using utf8),
bodytext=convert(cast(convert(bodytext using latin1) as binary) using utf8)
WHERE 1
You can also convert imagecaption, imagealttext, imagetitletext and keywords if needed. Hope this will help somebody migrating tt_news to new typo3 version.
From what you describe, it seems you have UTF-8 data that was originally stored as Latin-1 and then not converted correctly to UTF-8. The data is recoverable; you'll need a MySQL function like
convert(cast(convert(name using latin1) as binary) using utf8)
It's possible that you may need to omit the inner conversion, depending on how the data was altered during the encoding conversion.