ClickHouse

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#include <Processors/QueryPlan/ArrayJoinStep.h>
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#include <Processors/Transforms/ArrayJoinTransform.h>
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#include <Processors/Transforms/ExpressionTransform.h>
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#include <QueryPipeline/QueryPipelineBuilder.h>
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#include <Interpreters/ArrayJoinAction.h>
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#include <Interpreters/ExpressionActions.h>
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#include <IO/Operators.h>
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#include <Common/JSONBuilder.h>
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namespace DB
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{
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static ITransformingStep::Traits getTraits()
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{
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    return ITransformingStep::Traits
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    {
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        {
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            .returns_single_stream = false,
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            .preserves_number_of_streams = true,
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            .preserves_sorting = false,
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        },
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        {
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            .preserves_number_of_rows = false,
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        }
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    };
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}
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ArrayJoinStep::ArrayJoinStep(const DataStream & input_stream_, ArrayJoinActionPtr array_join_)
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    : ITransformingStep(
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        input_stream_,
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        ArrayJoinTransform::transformHeader(input_stream_.header, array_join_),
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        getTraits())
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    , array_join(std::move(array_join_))
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{
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}
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void ArrayJoinStep::updateOutputStream()
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{
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    output_stream = createOutputStream(
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        input_streams.front(), ArrayJoinTransform::transformHeader(input_streams.front().header, array_join), getDataStreamTraits());
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}
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void ArrayJoinStep::transformPipeline(QueryPipelineBuilder & pipeline, const BuildQueryPipelineSettings &)
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{
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    pipeline.addSimpleTransform([&](const Block & header, QueryPipelineBuilder::StreamType stream_type)
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    {
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        bool on_totals = stream_type == QueryPipelineBuilder::StreamType::Totals;
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        return std::make_shared<ArrayJoinTransform>(header, array_join, on_totals);
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    });
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}
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void ArrayJoinStep::describeActions(FormatSettings & settings) const
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{
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    String prefix(settings.offset, ' ');
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    bool first = true;
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    settings.out << prefix << (array_join->is_left ? "LEFT " : "") << "ARRAY JOIN ";
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    for (const auto & column : array_join->columns)
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    {
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        if (!first)
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            settings.out << ", ";
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        first = false;
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        settings.out << column;
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    }
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    settings.out << '\n';
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}
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void ArrayJoinStep::describeActions(JSONBuilder::JSONMap & map) const
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{
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    map.add("Left", array_join->is_left);
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    auto columns_array = std::make_unique<JSONBuilder::JSONArray>();
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    for (const auto & column : array_join->columns)
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        columns_array->add(column);
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    map.add("Columns", std::move(columns_array));
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}
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}
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