Обсуждение: Valued Predicates

In my reading of SQL for smarties I've stumbled across syntax that is supported by Postgresql.
However, I can't find mention of it in the Postgresql Docs.  Would an appropriate location for
this syntax be the "where condition" of the insert/update/select/delete statements?

i.e.

mydb=# select * from test2 where ( (a,b) >= (1,'A') ) is unknown;
 a | b
---+---
 3 |
(1 row)
mydb=# select * from test2 where ( (a,b) >= (1,'A') ) is true;
 a |   b
---+--------
 1 | Albert
 2 | Bert
(2 rows)
mydb=# select * from test2 where ( (a,b) >= (1,'A') ) is false;
 a | b
---+---
(0 rows)
mydb=# select * from test2 where ( (a,b) >= (1,'A') ) is not false;
 a |   b
---+--------
 1 | Albert
 2 | Bert
 3 |
(3 rows)
mydb=# select * from test2 where ( (a,b) >= (1,'A') ) is not true;
 a | b
---+---
 3 |
(1 row)
mydb=# select * from test2 where ( (a,b) >= (1,'A') ) is not true;
 a | b
---+---
 3 |
(1 row)

Regards,

Richard Broersma Jr.

Richard Broersma Jr <rabroersma@yahoo.com> writes:
> In my reading of SQL for smarties I've stumbled across syntax that is supported by Postgresql.
> However, I can't find mention of it in the Postgresql Docs.

Which part of this do you claim is not documented?  It looks to me like
it's all covered in one of

http://developer.postgresql.org/pgdocs/postgres/functions-comparison.html
http://developer.postgresql.org/pgdocs/postgres/functions-comparisons.html#ROW-WISE-COMPARISON

            regards, tom lane

> Which part of this do you claim is not documented?  It looks to me like
> it's all covered in one of
>
> http://developer.postgresql.org/pgdocs/postgres/functions-comparison.html
> http://developer.postgresql.org/pgdocs/postgres/functions-comparisons.html#ROW-WISE-COMPARISON

I see it now.  Sorry for the false static.

Regards,

Richard Broersma Jr.