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SUM analytic function in Oracle SQL | ||
The sum analytic function sums up all «previous» rows within a partition:
create table sum_example ( a number, b varchar2(10), c varchar2(10) ); insert into sum_example values ( 1, 'one' , 'group 1'); insert into sum_example values ( 2, 'two' , 'group 1'); insert into sum_example values ( 3, 'three' , 'group 1'); insert into sum_example values ( 10, 'ten' , 'group 2'); insert into sum_example values (null, 'null' , 'group 2'); insert into sum_example values ( 30, 'thirty', 'group 2'); insert into sum_example values ( 40, 'fourty', 'group 2'); select a, sum(a) over(partition by c order by b) from sum_example; A SUM(A)OVER(PARTITIONBYCORDERBYB) ---------- -------------------------------- 1 1 3 4 2 6 40 40 40 10 50 30 80 Links
On identifiying «periods of activity» is an example that uses sum.
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