spark技术分享Pivot Unary Logical Operator
Pivot is a unary logical operator that represents pivot operator.
Pivot is created when RelationalGroupedDataset creates a DataFrame for an aggregate operator.
Analysis Phase
Pivot operator is resolved at analysis phase in the following logical evaluation rules:
Pivot operator “disappears” behind (i.e. is converted to) a Aggregate logical operator (possibly under Project operator).
Creating Pivot Instance
Pivot takes the following when created:
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Grouping named expressions
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Pivot column expression
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Pivot values literals
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Aggregation expressions
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Child logical plan
