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 the array column, 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} Thank you so much, -- View this message in context: http://postgresql.1045698.n5.nabble.com/Aggeregate-funtion-calculating-the-average-value-of-each-same-index-of-an-array-column-in-a-table-tp5732388.html Sent from the PostgreSQL - general mailing list archive at Nabble.com. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general