When developing Drupal one often needs to pull recent copies of the live database into the dev environment.
Loading a dump into the dev database will update any existing tables, add any new ones - but it won't remove tables from the dev environment that re not in live.
This causes problems with Drupal as module install and update hooks may need to create tables which don't yet exist on live.
My solution which assumes you have .my.cnf set up to provide login locally is below.
# dump live db
ssh live "mysqldump livedb | gzip > /tmp/livedb.sql.gz"
# download live db
scp live:/tmp/livedb.sql.gz /tmp
# clean out dev db
mysql -BNe "show tables" devdb | awk '{print "drop table " $1 ";"} | mysql devdb
# copy live db to dev
zcat /tmp/livedb.sql.gz | mysql devdb
# make sure test mails never go to real users!
echo "update users set mail='me@example.com'" | mysql devdb