Rating: 

Gently introduces terms like "anti-join" in a very practical context, making them uniquely understandable.

Lack of coverage of MERGE ("UPSERT") statement, new in 9i, deplorable; it is useful not just in data warehousing.

And here's a trick from me: to insert a record without error if it already exists,

INSERT ALL INTO tab

(

a ,

b

)

SELECT

'foo' ,

'bar'

FROM

dual

WHERE

( NOT EXISTS

(

SELECT

1

FROM

tab

WHERE

( a = 'foo' )

AND

( b = 'bar' )

)

)

;