Many-to-Many Joins
•Many-to-many joins are almost
always wrong!
•Many-to-many
joins come from a combination of SQL errors and database-design
errors.
•DISTINCT
is a common band-aid that covers up most, but usually not
all of the row errors that result from erroneous
many-to-many joins! (I do not mean by this that the
resulting SQL is correct!)
•The
underlying problem calls for more than a partial, band-aid fix!