Here's one (of many) solutions:
CREATE OR REPLACE FUNCTION range( ANYELEMENT, ANYARRAY ) RETURNS INTEGER
LANGUAGE SQL AS
'SELECT CASE array_upper( $2, 1 ) WHEN 1 THEN 0 ELSE range( $1, $2[
1:(array_upper( $2, 1 ) - 1) ] ) END
+ CASE WHEN $1 > $2[ array_upper( $2, 1 ) ] THEN 1 ELSE 0 END; ';
Called as
SELECT range( 25, ARRAY[ 10, 20, 30, 40, 50 ] );
-- Dean
On 2005-10-13 09:48, Scott Marlowe wrote:
I have to admit, my thoughts on it were to build a query with case statements in it and execute it. That sounds about like you're proposing, right?
On Thu, 2005-10-13 at 11:30, Dean Gibson (DB Administrator) wrote:
What's the point of a binary search if the list is small enough to fit on a line or two? And if a query can be substituted for N1-NN, you have to read all the values anyway, and then the function is trivially expressed as a normal query with no decrease in speed.
-- Dean
On Wed, 2005-10-12 at 20:08, Michael Fuhr wrote:
Here's an excerpt from the MySQL documentation:
INTERVAL(N,N1,N2,N3,...)
Returns 0 if N < N1, 1 if N < N2 and so on or -1 if N is
NULL. All arguments are treated as integers. It is required
that N1 < N2 < N3 < ... < Nn for this function to work
correctly. This is because a binary search is used (very fast).
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