( ) . A B. , comp (a comp-op b), (a comp-op const), a b A B, const , comp-op .
A JOIN B WHERE comp A B , comp A B (A JOIN B WHERE comp (A TIMES B) WHERE comp).
, , - , (a comp-op b), a b -. , .
, , , - . , , - . comp , ( ) comp1 AND (a comp-op b), a b -.
, . {_, _, _, _} ( _ , ) {_, _, _} (_ , _ - , _ , ). . 4.7.
JOIN WHERE (_ > _) ( , , ). . 4.8.
( ), . , . , .
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(EQUIJOIN) , (NATURAL JOIN). , (a = b), a b . , , .
. 3.7.
A B, (, ) c (. . ). AB A B. A B AB A B A.c = B.c. , , , NATURAL JOIN.
. 4.9 JOIN ( RENAME (_, _1)) WHERE (_ = _) ( : , , - ) NATURAL JOIN ( , ).
. 3.8. JOIN WHERE (_ > _)
. 3.9.
, , , . , .