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Allow alias of single-column select to be used as select column (#542)

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This commit is contained in:
Roland Bock 2023-11-19 12:57:54 +01:00
parent 5c673603c3
commit 6cc2067ef5
6 changed files with 82 additions and 8 deletions
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22
include/sqlpp11/select_pseudo_table.h
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@ -50,11 +50,31 @@ namespace sqlpp
tag_if<tag::can_be_null, _can_be_null or _depends_on_outer_table>>;
};
template<typename... NamedExpr>
struct select_expression_type {
using value_t = no_value_t;
static constexpr bool _is_expression = false;
static constexpr bool _can_be_null = false;
};
template<typename NamedExpr>
struct select_expression_type<NamedExpr> {
using value_t = value_type_of<NamedExpr>;
static constexpr bool _is_expression = true;
static constexpr bool _can_be_null = can_be_null_t<NamedExpr>::value;
};
template <typename Select, typename... NamedExpr>
struct select_pseudo_table_t
: public table_t<select_pseudo_table_t<Select, NamedExpr...>, select_column_spec_t<Select, NamedExpr>...>
{
using _traits = make_traits<no_value_t,
using _expr_t = select_expression_type<NamedExpr...>;
using _traits = make_traits<
// Usage as named expression
typename _expr_t::value_t,
tag_if<tag::is_expression, _expr_t::_is_expression>,
tag_if<tag::can_be_null, _expr_t::_can_be_null>,
// Usage as table
tag::is_table,
tag::is_pseudo_table,
tag_if<tag::requires_parens, requires_parens_t<Select>::value>>;

1
include/sqlpp11/table_alias.h
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@ -44,6 +44,7 @@ namespace sqlpp
using _traits = make_traits<value_type_of<Table>,
tag::is_table,
tag::is_alias,
tag_if<tag::can_be_null, can_be_null_t<Table>::value>,
tag_if<tag::is_selectable, is_expression_t<Table>::value>>;
using _nodes = detail::type_vector<>;

1
tests/core/serialize/CMakeLists.txt
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@ -43,6 +43,7 @@ set(test_files
Min.cpp
Operator.cpp
Over.cpp
SelectAs.cpp
Some.cpp
Sum.cpp
TableAlias.cpp

43
tests/core/serialize/SelectAs.cpp Normal file
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@ -0,0 +1,43 @@
/*
* Copyright (c) 2023, Roland Bock
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "compare.h"
#include "Sample.h"
#include <sqlpp11/sqlpp11.h>
#include <iostream>
SQLPP_ALIAS_PROVIDER(cheese)
int SelectAs(int, char*[])
{
const auto foo = test::TabFoo{};
const auto bar = test::TabBar{};
// SELECT...AS as selectable column
compare(__LINE__, select(foo.omega, select(count(bar.alpha)).from(bar).unconditionally().as(cheese)), "SELECT tab_foo.omega,(SELECT COUNT(tab_bar.alpha) AS count_ FROM tab_bar) AS cheese");
return 0;
}

9
tests/core/usage/Select.cpp
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@ -61,6 +61,8 @@ void print_row(Row const& row)
std::cout << a << ", " << b << std::endl;
}
SQLPP_ALIAS_PROVIDER(cheese)
int Select(int, char*[])
{
MockDb db = {};
@ -164,6 +166,7 @@ int Select(int, char*[])
.dynamic_offset();
s.select_flags.add(sqlpp::distinct);
s.selected_columns.add(without_table_check(f.omega));
s.selected_columns.add(select(f.omega).from(f).unconditionally().as(f.delta));
s.from.add(dynamic_cross_join(f));
s.where.add(t.alpha > 7);
s.having.add(t.alpha > 7);
@ -210,5 +213,11 @@ int Select(int, char*[])
}
}
for (const auto& row :
db(select(f.omega, select(count(t.alpha)).from(t).unconditionally().as(cheese)).from(f).unconditionally()))
{
std::cout << row.omega << " " << row.cheese << std::endl;
}
return 0;
}

8
tests/core/usage/SelectType.cpp
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@ -260,9 +260,9 @@ int SelectType(int, char*[])
// Test an alias of a select of a single numeric table column
{
using T = decltype(select(t.alpha).from(t).as(alias::b));
static_assert(not sqlpp::is_numeric_t<T>::value, "type requirement");
static_assert(sqlpp::is_numeric_t<T>::value, "type requirement");
static_assert(not sqlpp::is_expression_t<T>::value, "type requirement");
static_assert(not sqlpp::is_selectable_t<T>::value, "type requirement");
static_assert(sqlpp::is_selectable_t<T>::value, "type requirement");
static_assert(not sqlpp::require_insert_t<T>::value, "type requirement");
static_assert(not sqlpp::must_not_insert_t<T>::value, "type requirement");
static_assert(not sqlpp::must_not_update_t<T>::value, "type requirement");
@ -276,9 +276,9 @@ int SelectType(int, char*[])
// Test the column of an alias of a select of an alias of a single numeric table column
{
using T = decltype(select(t.alpha.as(alias::a)).from(t).as(alias::b));
static_assert(not sqlpp::is_numeric_t<T>::value, "type requirement");
static_assert(sqlpp::is_numeric_t<T>::value, "type requirement");
static_assert(not sqlpp::is_expression_t<T>::value, "type requirement");
static_assert(not sqlpp::is_selectable_t<T>::value, "type requirement");
static_assert(sqlpp::is_selectable_t<T>::value, "type requirement");
static_assert(not sqlpp::require_insert_t<T>::value, "type requirement");
static_assert(not sqlpp::must_not_insert_t<T>::value, "type requirement");
static_assert(not sqlpp::must_not_update_t<T>::value, "type requirement");