mirror of
https://github.com/rbock/sqlpp11.git
synced 2024-11-16 12:51:13 +08:00
94 lines
2.6 KiB
C++
94 lines
2.6 KiB
C++
/*
|
|
* Copyright (c) 2013, 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.
|
|
*/
|
|
|
|
#ifndef SQLPP_AVG_H
|
|
#define SQLPP_AVG_H
|
|
|
|
#include <sstream>
|
|
#include <sqlpp11/type_traits.h>
|
|
|
|
namespace sqlpp
|
|
{
|
|
namespace detail
|
|
{
|
|
template<typename Expr>
|
|
struct avg_t: public floating_point::template operators<avg_t<Expr>>
|
|
{
|
|
static_assert(is_numeric_t<Expr>::value, "avg() requires a value expression as argument");
|
|
|
|
struct _value_type: public floating_point
|
|
{
|
|
using _is_named_expression = std::true_type;
|
|
};
|
|
|
|
struct _name_t
|
|
{
|
|
static constexpr const char* _get_name() { return "AVG"; }
|
|
template<typename T>
|
|
struct _member_t
|
|
{
|
|
T avg;
|
|
};
|
|
};
|
|
|
|
avg_t(Expr&& expr):
|
|
_expr(std::move(expr))
|
|
{}
|
|
|
|
avg_t(const Expr& expr):
|
|
_expr(expr)
|
|
{}
|
|
|
|
avg_t(const avg_t&) = default;
|
|
avg_t(avg_t&&) = default;
|
|
avg_t& operator=(const avg_t&) = default;
|
|
avg_t& operator=(avg_t&&) = default;
|
|
~avg_t() = default;
|
|
|
|
template<typename Db>
|
|
void serialize(std::ostream& os, Db& db) const
|
|
{
|
|
static_assert(Db::_supports_avg, "avg() not supported by current database");
|
|
os << "AVG(";
|
|
_expr.serialize(os, db);
|
|
os << ")";
|
|
}
|
|
|
|
private:
|
|
Expr _expr;
|
|
};
|
|
}
|
|
|
|
template<typename T>
|
|
auto avg(T&& t) -> typename detail::avg_t<typename operand_t<T, is_value_t>::type>
|
|
{
|
|
return { std::forward<T>(t) };
|
|
}
|
|
|
|
}
|
|
|
|
#endif
|