Hi,
I have a table with several lines as following;
- Create table mytable (type number , values integer [2]) ;
- Insert into mytable values (1, '{ 10, 0 }' );
- Insert into mytable values (1, '{ 20, 30 }' );
- Insert into mytable values (2, '{30, 60}' );
(In fact, the array size is very big (ex. values [10000]) but the size is
fix. In order to simplify the example, I used an array integer [2]).
I would like to obtain the average value of each index of values column.
Is it possible to create an aggregate function which can works as following
? :
(Suppose that avg_mytable is the aggregation function name.)
Ex1) Select avg_mytable (values) from mytable ;
avg_mytable (values)
------------------------
{ 20, 30}
(- Explication of the results: 20 because (10+20+30)/3 , 30 because
(0+30+60)/3)
Ex2) Select type, avg_mytable (values) from mytable Group by type ;
Type | avg_mytable (values)
---------------------------------------------
1 | { 15, 15}
2 | { 30, 60}
I searched in the documentation for "array functions" but I could not find
functions useful for me...
Thank you so much,
Lea
