mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-09-30 05:30:51 +00:00
290 lines
6.3 KiB
C++
290 lines
6.3 KiB
C++
#pragma once
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#include <ext/range.hpp>
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#include <DB/IO/WriteBuffer.h>
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#include <DB/IO/WriteHelpers.h>
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#include <DB/Dictionaries/writeParenthesisedString.h>
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#include <DB/Dictionaries/DictionaryStructure.h>
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int UNSUPPORTED_METHOD;
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}
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/** Генерирует запрос для загрузки данных из внешней БД.
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*/
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struct ExternalQueryBuilder
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{
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const DictionaryStructure & dict_struct;
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const std::string & db;
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const std::string & table;
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const std::string & where;
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ExternalQueryBuilder(
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const DictionaryStructure & dict_struct,
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const std::string & db,
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const std::string & table,
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const std::string & where)
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: dict_struct(dict_struct), db(db), table(table), where(where)
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{
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}
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/** Получить запрос на загрузку всех данных. */
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std::string composeLoadAllQuery() const
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{
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std::string query;
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{
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WriteBufferFromString out{query};
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writeString("SELECT ", out);
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if (dict_struct.id)
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{
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if (!dict_struct.id.value().expression.empty())
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{
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writeParenthesisedString(dict_struct.id.value().expression, out);
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writeString(" AS ", out);
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}
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writeProbablyBackQuotedString(dict_struct.id.value().name, out);
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if (dict_struct.range_min && dict_struct.range_max)
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{
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writeString(", ", out);
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if (!dict_struct.range_min.value().expression.empty())
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{
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writeParenthesisedString(dict_struct.range_min.value().expression, out);
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writeString(" AS ", out);
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}
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writeProbablyBackQuotedString(dict_struct.range_min.value().name, out);
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writeString(", ", out);
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if (!dict_struct.range_max.value().expression.empty())
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{
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writeParenthesisedString(dict_struct.range_max.value().expression, out);
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writeString(" AS ", out);
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}
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writeProbablyBackQuotedString(dict_struct.range_max.value().name, out);
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}
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}
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else if (dict_struct.key)
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{
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auto first = true;
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for (const auto & key : *dict_struct.key)
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{
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if (!first)
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writeString(", ", out);
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first = false;
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if (!key.expression.empty())
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{
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writeParenthesisedString(key.expression, out);
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writeString(" AS ", out);
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}
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writeProbablyBackQuotedString(key.name, out);
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}
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}
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for (const auto & attr : dict_struct.attributes)
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{
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writeString(", ", out);
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if (!attr.expression.empty())
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{
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writeParenthesisedString(attr.expression, out);
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writeString(" AS ", out);
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}
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writeProbablyBackQuotedString(attr.name, out);
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}
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writeString(" FROM ", out);
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if (!db.empty())
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{
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writeProbablyBackQuotedString(db, out);
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writeChar('.', out);
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}
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writeProbablyBackQuotedString(table, out);
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if (!where.empty())
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{
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writeString(" WHERE ", out);
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writeString(where, out);
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}
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writeChar(';', out);
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}
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return query;
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}
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/** Получить запрос на загрузку данных по множеству простых ключей. */
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std::string composeLoadIdsQuery(const std::vector<std::uint64_t> & ids)
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{
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if (!dict_struct.id)
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throw Exception{"Simple key required for method", ErrorCodes::UNSUPPORTED_METHOD};
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std::string query;
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{
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WriteBufferFromString out{query};
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writeString("SELECT ", out);
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if (!dict_struct.id.value().expression.empty())
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{
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writeParenthesisedString(dict_struct.id.value().expression, out);
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writeString(" AS ", out);
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}
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writeProbablyBackQuotedString(dict_struct.id.value().name, out);
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for (const auto & attr : dict_struct.attributes)
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{
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writeString(", ", out);
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if (!attr.expression.empty())
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{
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writeParenthesisedString(attr.expression, out);
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writeString(" AS ", out);
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}
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writeProbablyBackQuotedString(attr.name, out);
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}
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writeString(" FROM ", out);
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if (!db.empty())
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{
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writeProbablyBackQuotedString(db, out);
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writeChar('.', out);
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}
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writeProbablyBackQuotedString(table, out);
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writeString(" WHERE ", out);
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if (!where.empty())
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{
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writeString(where, out);
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writeString(" AND ", out);
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}
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writeProbablyBackQuotedString(dict_struct.id.value().name, out);
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writeString(" IN (", out);
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auto first = true;
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for (const auto id : ids)
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{
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if (!first)
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writeString(", ", out);
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first = false;
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writeString(DB::toString(id), out);
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}
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writeString(");", out);
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}
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return query;
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}
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/** Получить запрос на загрузку данных по множеству сложных ключей. */
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std::string composeLoadKeysQuery(
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const ConstColumnPlainPtrs & key_columns, const std::vector<std::size_t> & requested_rows)
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{
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if (!dict_struct.key)
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throw Exception{"Composite key required for method", ErrorCodes::UNSUPPORTED_METHOD};
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std::string query;
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{
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WriteBufferFromString out{query};
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writeString("SELECT ", out);
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auto first = true;
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for (const auto & key_or_attribute : boost::join(*dict_struct.key, dict_struct.attributes))
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{
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if (!first)
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writeString(", ", out);
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first = false;
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if (!key_or_attribute.expression.empty())
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{
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writeParenthesisedString(key_or_attribute.expression, out);
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writeString(" AS ", out);
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}
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writeProbablyBackQuotedString(key_or_attribute.name, out);
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}
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writeString(" FROM ", out);
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if (!db.empty())
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{
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writeProbablyBackQuotedString(db, out);
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writeChar('.', out);
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}
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writeProbablyBackQuotedString(table, out);
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writeString(" WHERE ", out);
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if (!where.empty())
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{
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writeString(where, out);
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writeString(" AND ", out);
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}
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first = true;
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for (const auto row : requested_rows)
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{
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if (!first)
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writeString(" OR ", out);
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first = false;
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composeKeyCondition(key_columns, row, out);
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}
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writeString(";", out);
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}
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return query;
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}
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private:
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void composeKeyCondition(const ConstColumnPlainPtrs & key_columns, const std::size_t row, WriteBuffer & out) const
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{
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writeString("(", out);
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const auto keys_size = key_columns.size();
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auto first = true;
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for (const auto i : ext::range(0, keys_size))
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{
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if (!first)
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writeString(" AND ", out);
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first = false;
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const auto & key_description = (*dict_struct.key)[i];
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/// key_i=value_i
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writeString(key_description.name, out);
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writeString("=", out);
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key_description.type->serializeTextQuoted(*key_columns[i], row, out);
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}
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writeString(")", out);
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}
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};
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}
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