1. 集合操作

?

?

?

WITHaAS ( SELECT 1 id

UNION

SELECT 2

),

bAS ( SELECT 1 id

UNION

SELECT 3

)

SELECT*

FROMa

EXCEPT

SELECT*

FROMb;

?

WITHaAS ( SELECT 1 id

UNION

SELECT 2

),

bAS ( SELECT 1 id

UNION

SELECT 3

)

SELECT*

FROMa

INTERSECT

SELECT*

FROMb

?

?