2017-12-26 21:34:06 +00:00
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#pragma once
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#include <Core/Types.h>
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2017-12-27 21:45:05 +00:00
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#include <Core/NamesAndTypes.h>
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2017-12-26 21:34:06 +00:00
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namespace DB
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{
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class IAST;
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class Context;
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/** For given ClickHouse query,
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* creates another query in a form of
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*
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* SELECT columns... FROM db.table WHERE ...
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*
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* where 'columns' are all required columns to read from "left" table of original query,
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* and WHERE contains subset of (AND-ed) conditions from original query,
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* that contain only compatible expressions.
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*
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* Compatible expressions are comparisons of identifiers, constants, and logical operations on them.
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*
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* NOTE There are concerns with proper quoting of identifiers for remote database.
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* Some databases use `quotes` and other use "quotes".
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*/
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String transformQueryForExternalDatabase(
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const IAST & query,
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const NamesAndTypesList & available_columns,
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const String & database,
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const String & table,
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const Context & context);
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}
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