Sams Teach Yourself SQL in 21 Days, Fourth Edition

Joining Tables Based on Nonequality

Because SQL supports an equi-join, you might assume that SQL also has a non-equi-join. You would be right! Whereas the equi-join uses an = sign in the WHERE statement, the non-equi-join uses everything but an = sign—for example,

						SELECT O.NAME, O.PARTNUM, P.PARTNUM,
						O.QUANTITY * P.PRICE TOTAL
						FROM ORDERS O, PART P
						WHERE O.PARTNUM > P.PARTNUM

NAME           PARTNUM     PARTNUM       TOTAL
========== =========== =========== ===========

TRUE WHEEL          76          54      162.75
BIKE SPEC           76          54      596.75
LE SHOPPE           76          54      271.25
AAA BIKE            76          54      217.00
JACKS BIKE          76          54      759.50
TRUE WHEEL          76          42       73.50
BIKE SPEC           54          42      245.00
BIKE SPEC           76          42      269.50
LE SHOPPE           76          42      122.50
AAA BIKE 76 42 98.00 AAA BIKE 46 42 343.00 JACKS BIKE 76 42 343.00 TRUE WHEEL 76 46 45.75 ...