Right, I am probably wrong. Some other opinion?
d
Le 15/11/11 19:48,
jmscott@setspace.com a écrit :
here is a trivial example in 9.1
jmscott=> select (1, 2) in (select 1, 2);?column?
----------t
(1 row)
where the right hand side returns 2 columns, not exactly one column,
contradicting what the docs say:
The right-hand side is a parenthesized subquery, which must return exactly one column.
seems like a documentation error. what am i missing?
-j
well, it seems to me that section 9.20.2 makes sense.
http://www.w3schools.com/sql/sql_in.asp
I am not sure that you can compare multiple columns such as in:
SELECT * FROM Persons WHERE LastName, FirstName IN (SELECT LastName,
FirstName FROM OtherPersons);
if this is what you mean, at least not using this method, which returns
an error.
d
Le 15/11/11 18:29, jmscott@setspace.com a écrit :
I would like clarification on the first paragraph of section 9.20.2 on
the page at
http://www.postgresql.org/docs/9.1/static/functions-subquery.html
regarding the syntax of the 'expression in (subquery)' clause.
What is meant by
The right-hand side is a parenthesized subquery, which must return exactly one column.
? Appears to me that the subquery must only contain the same number of
columns as the left hand side, not just 1 column.
thanks-j
--
Baux David
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