43 lines
1.2 KiB
C
43 lines
1.2 KiB
C
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/**
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* @file mix_cc/sql/where.h
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* @brief 查询条件
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* @author Cat (null.null.null@qq.com)
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* @version 0.1
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* @date 2021-09-17
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*
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* Copyright: Baosight Co. Ltd.
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* DO NOT COPY/USE WITHOUT PERMISSION
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*
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*/
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#pragma once
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#include <mix_cc/sql/public.h>
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#include <mix_cc/sql/condition.h>
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#include <mix_cc/sql/statement.h>
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#include <string>
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#include <algorithm>
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namespace mix_cc {
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namespace sql {
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template <typename PrevStatement, typename... Conditions>
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struct where_t : public prev_statement_t<PrevStatement>, public statement_t {
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static constexpr auto s_text = op::cmd_t::where;
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constexpr explicit where_t(PrevStatement prev_st, Conditions... conditions)
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: prev_statement_t<PrevStatement>(prev_st), conditions_(conditions...) {}
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constexpr auto get_command() {
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auto sel_str_c = " "_s + s_text + " "_s;
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auto conditions_str =
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hana::transform(conditions_, [](auto col) { return col.get_str(); });
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auto r_str = hana::fold_left(conditions_str, [](auto cond1, auto cond2) {
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return cond1 + " AND " + cond2;
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});
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return std::string(sel_str_c.c_str()) + r_str;
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}
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hana::tuple<Conditions...> conditions_;
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};
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} // namespace sql
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} // namespace mix_cc
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