21 lines
894 B
Markdown
21 lines
894 B
Markdown
Find the breaks for N categories in a numerical column based on the [Heads/Tails optimization](http://arxiv.org/pdf/1209.2801v1.pdf). Below, Heads/Tails used to color based on the area of the polygons.
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#### Using the function
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We can determine the 7 most optimal breaks in a column of numerical data as follows,
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```sql
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SELECT CDB_HeadsTailsBins(array_agg(numeric_column), 7) FROM table_name
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-- Results in an ordered array like, {7824,23492,52696,233857,666089,1001709,1638094}
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-- Each break happens up to, and equal, to a number:
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-- (bin1 is less than or equal to 7824, bin2 is less than or equal to 23492, etc.)
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```
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#### Arguments
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CDB_HeadsTailsBins(in_array, breaks)
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* **in_array** numeric[]. A NUMERIC array of values.
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* **breaks** int. The number of categories you want to create |