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Implementaion of window function nth_value.
1. Implemented the window function nth_value 2. Make the return type of lag/lead, and nth_value functions to be ColumnNullable, thus the returned value can be null if it is out of frame.
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ryzuo
parent
2796aa333f
commit
4eb053a303
@ -1558,9 +1558,85 @@ struct WindowFunctionLagLeadInFrame final : public WindowFunction
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else
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{
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// Offset is inside the frame.
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to.insertFrom(*transform->blockAt(target_row).input_columns[
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workspace.argument_column_indices[0]],
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target_row.row);
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auto ptr = ColumnNullable::create(transform->blockAt(target_row).input_columns[
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workspace.argument_column_indices[0]],
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ColumnUInt8::create());
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to.insertFrom(*ptr, target_row.row);
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}
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}
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};
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struct WindowFunctionNthValue final : public WindowFunction
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{
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WindowFunctionNthValue(const std::string & name_,
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const DataTypes & argument_types_, const Array & parameters_)
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: WindowFunction(name_, argument_types_, parameters_)
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{
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if (!parameters.empty())
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{
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throw Exception(ErrorCodes::BAD_ARGUMENTS,
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"Function {} cannot be parameterized", name_);
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}
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if (argument_types.empty())
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{
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throw Exception(ErrorCodes::BAD_ARGUMENTS,
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"Function {} takes at least one argument", name_);
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}
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if(argument_types.size() != 2)
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{
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throw Exception(ErrorCodes::BAD_ARGUMENTS,
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"Function '{}' accepts 2 arguments, {} given",
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name_, argument_types.size());
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}
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}
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DataTypePtr getReturnType() const override
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{ return argument_types[0]; }
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bool allocatesMemoryInArena() const override { return false; }
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void windowInsertResultInto(const WindowTransform * transform,
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size_t function_index) override
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{
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const auto & current_block = transform->blockAt(transform->current_row);
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IColumn & to = *(current_block.output_columns[function_index]);
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const auto & workspace = transform->workspaces[function_index];
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int64_t offset = (*current_block.input_columns[
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workspace.argument_column_indices[1]])[
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transform->current_row.row].get<Int64>() - 1;
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if (offset < 0)
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{
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throw Exception(ErrorCodes::BAD_ARGUMENTS,
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"The offset for function {} must be non-negative, {} given",
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getName(), offset);
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}
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if (offset > INT_MAX)
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{
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throw Exception(ErrorCodes::BAD_ARGUMENTS,
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"The offset for function {} must be less than {}, {} given",
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getName(), INT_MAX, offset);
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}
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const auto [target_row, offset_left] = transform->moveRowNumber(transform->frame_start, offset);
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if (offset_left != 0
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|| target_row < transform->frame_start
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|| transform->frame_end <= target_row)
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{
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// Offset is outside the frame.
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to.insertDefault();
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}
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else
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{
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// Offset is inside the frame.
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auto ptr = ColumnNullable::create(transform->blockAt(target_row).input_columns[
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workspace.argument_column_indices[0]],
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ColumnUInt8::create());
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to.insertFrom(*ptr, target_row.row);
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}
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}
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};
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@ -1628,6 +1704,13 @@ void registerWindowFunctions(AggregateFunctionFactory & factory)
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return std::make_shared<WindowFunctionLagLeadInFrame<true>>(
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name, argument_types, parameters);
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}, properties});
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factory.registerFunction("nth_value", {[](const std::string & name,
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const DataTypes & argument_types, const Array & parameters, const Settings *)
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{
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return std::make_shared<WindowFunctionNthValue>(
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name, argument_types, parameters);
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}, properties});
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}
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}
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@ -1095,6 +1095,48 @@ order by number
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7 6 8
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8 7 9
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9 8 9
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-- nth_value without specific frame range given
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select
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number,
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nth_value(number, 1) over w as firstValue,
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nth_value(number, 2) over w as secondValue,
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nth_value(number, 3) over w as thirdValue,
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nth_value(number, 4) over w as fourthValue
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from numbers(10)
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window w as (order by number)
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order by number
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;
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0 0 NULL NULL NULL
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1 0 1 NULL NULL
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2 0 1 2 NULL
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3 0 1 2 3
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4 0 1 2 3
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5 0 1 2 3
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6 0 1 2 3
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7 0 1 2 3
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8 0 1 2 3
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9 0 1 2 3
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-- nth_value with frame range specified
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select
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number,
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nth_value(number, 1) over w as firstValue,
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nth_value(number, 2) over w as secondValue,
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nth_value(number, 3) over w as thirdValue,
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nth_value(number, 4) over w as fourthValue
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from numbers(10)
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window w as (order by number range between 1 preceding and 1 following)
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order by number
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;
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0 0 1 NULL NULL
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1 0 1 2 NULL
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2 1 2 3 NULL
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3 2 3 4 NULL
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4 3 4 5 NULL
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5 4 5 6 NULL
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6 5 6 7 NULL
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7 6 7 8 NULL
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8 7 8 9 NULL
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9 8 9 NULL NULL
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-- In this case, we had a problem with PartialSortingTransform returning zero-row
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-- chunks for input chunks w/o columns.
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select count() over () from numbers(4) where number < 2;
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@ -1136,31 +1178,3 @@ select count() over (rows between 2147483648 preceding and 2147493648 following)
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select count() over () from (select 1 a) l inner join (select 2 a) r using a;
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-- This case works as expected, one empty input chunk marked as input end.
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select count() over () where null;
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-- Inheriting another window.
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select number, count() over (w1 rows unbounded preceding) from numbers(10)
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window
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w0 as (partition by intDiv(number, 5) as p),
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w1 as (w0 order by mod(number, 3) as o)
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order by p, o, number
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;
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0 1
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3 2
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1 3
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4 4
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2 5
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6 1
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9 2
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7 3
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5 4
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8 5
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-- can't redefine PARTITION BY
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select count() over (w partition by number) from numbers(1) window w as (partition by intDiv(number, 5)); -- { serverError 36 }
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-- can't redefine existing ORDER BY
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select count() over (w order by number) from numbers(1) window w as (partition by intDiv(number, 5) order by mod(number, 3)); -- { serverError 36 }
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-- parent window can't have frame
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select count() over (w range unbounded preceding) from numbers(1) window w as (partition by intDiv(number, 5) order by mod(number, 3) rows unbounded preceding); -- { serverError 36 }
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-- looks weird but probably should work -- this is a window that inherits and changes nothing
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select count() over (w) from numbers(1) window w as ();
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1
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-- nonexistent parent window
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select count() over (w2 rows unbounded preceding); -- { serverError 36 }
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@ -403,6 +403,30 @@ window w as (order by number range between 1 preceding and 1 following)
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order by number
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;
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-- nth_value without specific frame range given
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select
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number,
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nth_value(number, 1) over w as firstValue,
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nth_value(number, 2) over w as secondValue,
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nth_value(number, 3) over w as thirdValue,
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nth_value(number, 4) over w as fourthValue
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from numbers(10)
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window w as (order by number)
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order by number
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;
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-- nth_value with frame range specified
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select
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number,
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nth_value(number, 1) over w as firstValue,
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nth_value(number, 2) over w as secondValue,
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nth_value(number, 3) over w as thirdValue,
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nth_value(number, 4) over w as fourthValue
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from numbers(10)
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window w as (order by number range between 1 preceding and 1 following)
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order by number
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;
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-- In this case, we had a problem with PartialSortingTransform returning zero-row
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-- chunks for input chunks w/o columns.
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select count() over () from numbers(4) where number < 2;
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@ -439,26 +463,3 @@ select count() over (rows between 2147483648 preceding and 2147493648 following)
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select count() over () from (select 1 a) l inner join (select 2 a) r using a;
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-- This case works as expected, one empty input chunk marked as input end.
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select count() over () where null;
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-- Inheriting another window.
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select number, count() over (w1 rows unbounded preceding) from numbers(10)
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window
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w0 as (partition by intDiv(number, 5) as p),
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w1 as (w0 order by mod(number, 3) as o)
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order by p, o, number
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;
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-- can't redefine PARTITION BY
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select count() over (w partition by number) from numbers(1) window w as (partition by intDiv(number, 5)); -- { serverError 36 }
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-- can't redefine existing ORDER BY
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select count() over (w order by number) from numbers(1) window w as (partition by intDiv(number, 5) order by mod(number, 3)); -- { serverError 36 }
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-- parent window can't have frame
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select count() over (w range unbounded preceding) from numbers(1) window w as (partition by intDiv(number, 5) order by mod(number, 3) rows unbounded preceding); -- { serverError 36 }
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-- looks weird but probably should work -- this is a window that inherits and changes nothing
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select count() over (w) from numbers(1) window w as ();
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-- nonexistent parent window
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select count() over (w2 rows unbounded preceding); -- { serverError 36 }
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