Re: how to generate a list of distinct scalar values from a column which type is array

am  Wed, dem 21.02.2007, um 19:21:09 +0100 mailte Sergio Andreozzi folgendes:
> Dear all,
> 
> given a column which type is for instance varchar(20)[], is there any SQL
> command that let me generate the list of distinct scalar values?
> 
> 
> e.g.:
>              col1
> row 1: (aaa, bb, c)
> row 2: (dddd, eeee)
> row 3: (aaa, eeee)
> 
> the query should return:
> 
> aaa
> bb
> c
> dddd
> eeee

Okay, next solution:

test=*# select * from a;     c
-------------{aaa,bb,c}{dddd,eeee}{aaa,eeee}
(3 rows)


test=*# select distinct c[s] from a,  generate_series(1,3)s where c[s] is not null; c
------aaabbcddddeeee
(5 rows)


You need to know the greatest upper dimension of the array, in this case
3, for the generate_series - function.


Andreas
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Andreas Kretschmer
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