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SQL. Between, IN, LIKE, IS NULL




Between A and B A B. , , . Not Between A and B, , , .

 

IN () , . . NOT IN (), , .
LIKE NOT LIKE. LIKE , , , , . NOT LIKE .

:

(_) ;
(%) ;

 

, , .
IS NULL. . , . . : . :

< >IS NULL < > IS NOT NULL.

( ) , IS NULL "" (TRUE), IS NOT NULL "" (FALSE), IS NULL "", IS NOT NULL ""

 

 


 

.

UNION, EXCEPT, INTERSECT , . , , .

R S , , R, S .

SELECT R.a1, R.a2

FROM R

UNION

SELECT S.b2, S.b1

FROM S

, , :

SELECT , AS /

FROM

UNION

SELECT _, AS /

FROM

R S , , .

(SELECT R.a1, R.a2

FROM R)

INTERSECT

(SELECT S.b2, S.b1

FROM S)

SELECT R.a1, R.a2

FROM R,S

WHERE R.a1=S.b1 AND R.a2=S.b2

 

SELECT R.a1, R.a2

FROM R

WHERE R.a1 IN

(SELECT S.b1 FROM S

WHERE S.b1=R.a1) AND R.a2 IN

(SELECT S.b2

FROM S

WHERE S.b2=R.a2)

, ,

(SELECT

FROM )

INTERSECT

(SELECT _

FROM )

R S , , R, S.

SELECT R.a1, R.a2

FROM R

WHERE NOT EXISTS

(SELECT S.b1,S.b2

FROM S

WHERE S.b1=R.a2 AND S.b2=R.a1)

(SELECT R.a1, R.a2

FROM R)

EXCEPT

(SELECT S.b1,S.b2

FROM S)

, ,

(SELECT

FROM )

EXCEPT

(SELECT _

FROM )

 

 


 

.

SQL . , ( WHERE HAVING), , . EXISTS, , .

, , -. FROM SELECT , . AS, . FROM :

FROM R1 AS A, R1 AS B

FROM R1 A, R1 B;

SELECT R1.

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