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78f4ee385f
count(col), unlike count(*), does not count rows for which col is NULL. However, if col's data type is not a scalar (e.g. a collection, tuple, or user-defined type) it behaves like count(*), counting NULLs too. The cause is that get_dynamic_aggregate() converts count() to the count(*) version. It works for scalars because get_dynamic_aggregate() intentionally fails to match scalar arguments, and functions::get() then matches the arguments against the pre-declared count functions. As we can only pre-declare count(scalar) (there's an infinite number of non-scalar types), we change the approach to be the same as min/max: we make count() a generic function. In fact count(col) is much better as a generic function, as it only examines its input to see if it is NULL. A unit test is added. It passes with Cassandra as well. Fixes #14198. Closes #14199
42 lines
977 B
C++
42 lines
977 B
C++
/*
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* Copyright (C) 2014-present ScyllaDB
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*
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* Modified by ScyllaDB
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*/
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/*
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* SPDX-License-Identifier: (AGPL-3.0-or-later and Apache-2.0)
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*/
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#pragma once
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#include "aggregate_function.hh"
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namespace cql3 {
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namespace functions {
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/// Factory methods for aggregate functions.
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namespace aggregate_fcts {
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static const sstring COUNT_ROWS_FUNCTION_NAME = "countRows";
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/// The function used to count the number of rows of a result set. This function is called when COUNT(*) or COUNT(1)
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/// is specified.
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shared_ptr<aggregate_function>
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make_count_rows_function();
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/// The same as `make_max_function()' but with type provided in runtime.
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shared_ptr<aggregate_function>
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make_max_function(data_type io_type);
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/// The same as `make_min_function()' but with type provided in runtime.
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shared_ptr<aggregate_function>
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make_min_function(data_type io_type);
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/// count(col) function for the specified type
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shared_ptr<aggregate_function> make_count_function(data_type input_type);
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}
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}
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}
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