Processing involving analytic functions involves three phases:
1. computation of products, selections, grouping, and having clauses;
2. application of analytic functions to the resulting sets of rows;
3. processing of the final order by clauses.
The results of the first phase can be partitioned. Partitions are created after the groups defined by the group by clauses and, thus, may use any aggregate functions such as sum, count, etc.
For each row in a partition, a sliding window of data may be defined. The window determines a sequence of rows that is used to perform calculations for the current row. Window sizes can be specified as numbers of rows or can be determined by intervals in a domain. Either end of a window or both ends can move, depending on the definition of the window.
Each computation involving an analytic function is based on a current row . This row serves as reference for the ends of the window.
Processing involving analytic functions involves three phases:
1. computation of products, selections, grouping, and having clauses;
2. application of analytic functions to the resulting sets of rows;
3. processing of the final order by clauses.
The results of the first phase can be partitioned. Partitions are created after the groups defined by the group by clauses and, thus, may use any aggregate functions such as sum, count, etc.
For each row in a partition, a sliding window of data may be defined. The window determines a sequence of rows that is used to perform calculations for the current row. Window sizes can be specified as numbers of rows or can be determined by intervals in a domain. Either end of a window or both ends can move, depending on the definition of the window.
Each computation involving an analytic function is based on a current row . This row serves as reference for the ends of the window.
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