22 Jun
2006
22 Jun
'06
12:18 a.m.
You wrote....
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"
I think I'd need more explanation. I'm not sure exactly what you're
expressing. Example data would help? Also, Pick generally didn't really have
a concept of datatyping. Everything was always stored as strings. Anything
that needed to be treated as numeric was converted on the fly during runtime
as indicated by context.
Jay