Oops… The English teacher just realized that she accidentally switched
oral_exam_scores. The last
UPDATE introduced another mistake to the
exam table, again with all records for English exams. How can we correct this? Look at the query below:
written_exam_score = oral_exam_score,
oral_exam_score = written_exam_score
WHERE subject = 'English'
We set new values for two columns:
oral_exam_score. The first column took the value from
oral_exam_score, and the second column took the value from
written_exam_score. SQL makes this operation easy.