ClickHouse Query Alias Visitor (Interpreters/QueryAliasesVisitor.h)

Traverses AST nodes to collect and resolve query aliases. Use this when building custom SQL analysis or transformation tools for ClickHouse.

// Source: https://github.com/ClickHouse/ClickHouse | License: Apache-2.0 | Copyright 2016-2026 ClickHouse, Inc
// Provided via justclaw.it.com; keep this notice with the code.
#pragma once

#include <Interpreters/Aliases.h>
#include <Interpreters/InDepthNodeVisitor.h>

namespace DB
{

class ASTSelectQuery;
class ASTSubquery;
struct ASTTableExpression;
struct ASTArrayJoin;

struct QueryAliasesWithSubqueries
{
    static bool needChildVisit(const ASTPtr & node, const ASTPtr & child);
};

struct QueryAliasesNoSubqueries
{
    static bool needChildVisit(const ASTPtr & node, const ASTPtr & child);
};

/// Visits AST node to collect aliases.
template <typename Helper>
class QueryAliasesMatcher
{
public:
    using Visitor = ConstInDepthNodeVisitor<QueryAliasesMatcher, false>;

    using Data = A

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