The usage of Analytical function and aggregate function commonly used in oracle

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According to the previous plan, finish this record today, so as to record your growth.

1. Syntax and usage of several ranking functions:

Rank () over ([partition by col] order by col)

Dense_rank () over ([partition by col] order by col)

Rownumber () over ([partition by col] order by col)

Rank () is a function of ranking. The function group will be sorted with a jump mark, and those with the same score will be juxtaposed.

Dense_rank () this function does not jump, the same score is tied for the first, the next is the second.

Row_number () can sort within a group (if there is a partition by) after sorting by a field through over.

The following picture shows the test results. Let's take a look at the picture and digest it:

Here is the code:

With lcy as (select regexp_substr ('10, 20, 30, 30, 50, 60, 80, 90, 100) score from dual connect by level