Ran into a totally from-left field bug today, and was surprised to find
that WHERE clauses against VARCHAR fields are totally case insensitive.
So if you have two rows in table FOO that have values "Bar" and "bar",
and you run SELECT * FROM Foo WHERE FIELD = 'Bar' -- you will
actually get BOTH 'Bar' and 'bar' rows returned.
Now there are ways in which you can set a particular column to always
be treated in a case sensitive manner.
But the simple/braindead fix to make your query case sensitive is to
use this instead: SELECT * FROM FOO WHERE FIELD LIKE BINARY 'Bar'
-- running that will cause case sensitive behavior to occur and only
one row to be returned.
And knowing is half the battle.