Обсуждение: Min and max element of an array column

Hello,
is it possible to obtain the minimum and the maximum single element of 
an array column?

Example:
[1, 2 ,5]
[3, -1, 6]
[9, 18,-4 ]

I'd just like to make a query that gives me the min (-4) and the max(18) 
of the column. Is that possible without a function? Thanks

In response to Gianvito Pio :
> Hello,
> is it possible to obtain the minimum and the maximum single element of 
> an array column?
> 
> Example:
> [1, 2 ,5]
> [3, -1, 6]
> [9, 18,-4 ]
> 
> I'd just like to make a query that gives me the min (-4) and the max(18) 
> of the column. Is that possible without a function? Thanks

test=*# select * from pio;    i
-----------{1,2,5}{3,-1,6}{9,18,-4}
(3 rows)

test=*# select min(unnest), max(unnest) from (select unnest(i) from pio)
foo;min | max
-----+----- -4 |  18
(1 row)



It is 8.4, if you have a version < 8.4, you need the unnest-function:

CREATE OR REPLACE FUNCTION unnest(ANYARRAY) RETURNS SETOF ANYELEMENT
LANGUAGE SQL AS $$SELECT $1[i] FROM
generate_series(array_lower($1,1),array_upper($1,1)) i;$$;

(with Thx to David Fetter)


Andreas
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