21 Jun
2006
21 Jun
'06
11:07 p.m.
Jay West wrote:
You wrote...
So, how would you implement this example?
SELECT book, author FROM titles
WHERE isbn_publisher(book) > isbn_publisher('1-234-56789-X'::isbn);
Specifically:
- return the values of the "book" and "author" fields
- from the "titles" table
- for those records in which the "isbn_publisher()" [1] function
returns a value that exceeds that of the isbn_publisher()'s
value for the isbn data type [2] corresponding to the string
representation "1-234-56789-X"
[1] defined a returning the value of the Publisher Identifier
in the ISBN argument -- "234" in the second instance, here
[2] the "::isbn" is an explicit type cast in this case from
a string to an "isbn"
That depends. For example, SQL requires a
terminating semicolon.
And, uses parens in many cases. Plus commas, etc. And, of course,
any expressional notation uses typical punctuation.
Pick et. al. didn't use
punctionation, no commas, no periods, no
parenthesis... just the obvious comparison operators and quotes.