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53 lines
1.3 KiB
C++
53 lines
1.3 KiB
C++
#include <Processors/Transforms/ExpressionTransform.h>
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#include <Interpreters/ExpressionAnalyzer.h>
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namespace DB
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{
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static Block transformHeader(Block header, const ExpressionActionsPtr & expression)
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{
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expression->execute(header, true);
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return header;
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}
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ExpressionTransform::ExpressionTransform(const Block & header_, ExpressionActionsPtr expression_, bool on_totals_, bool default_totals_)
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: ISimpleTransform(header_, transformHeader(header_, expression_), on_totals_)
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, expression(std::move(expression_))
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, on_totals(on_totals_)
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, default_totals(default_totals_)
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{
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}
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void ExpressionTransform::transform(Chunk & chunk)
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{
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if (!initialized)
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{
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initialized = true;
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if (expression->resultIsAlwaysEmpty())
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{
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stopReading();
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chunk = Chunk(getOutputPort().getHeader().getColumns(), 0);
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return;
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}
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}
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auto block = getInputPort().getHeader().cloneWithColumns(chunk.detachColumns());
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if (on_totals)
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{
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if (default_totals && !expression->hasTotalsInJoin())
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return;
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expression->executeOnTotals(block);
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}
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else
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expression->execute(block);
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auto num_rows = block.rows();
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chunk.setColumns(block.getColumns(), num_rows);
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}
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}
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