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#include <Parsers/ASTWithAlias.h>
#include <IO/WriteHelpers.h>
#include <IO/Operators.h>
namespace DB
{
static void writeAlias(const String & name, const ASTWithAlias::FormatSettings & settings)
{
settings.ostr << (settings.hilite ? IAST::hilite_keyword : "") << " AS " << (settings.hilite ? IAST::hilite_alias : "");
settings.writeIdentifier(name);
settings.ostr << (settings.hilite ? IAST::hilite_none : "");
}
void ASTWithAlias::formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const
{
/// If we have previously output this node elsewhere in the query, now it is enough to output only the alias.
/// This is needed because the query can become extraordinary large after substitution of aliases.
if (!alias.empty() && !state.printed_asts_with_alias.emplace(frame.current_select, alias, getTreeHash()).second)
{
settings.ostr << (settings.hilite ? IAST::hilite_identifier : "");
settings.writeIdentifier(alias);
settings.ostr << (settings.hilite ? IAST::hilite_none : "");
}
else
{
/// If there is an alias, then parentheses are required around the entire expression, including the alias.
/// Because a record of the form `0 AS x + 0` is syntactically invalid.
if (frame.need_parens && !alias.empty())
settings.ostr << '(';
formatImplWithoutAlias(settings, state, frame);
if (!alias.empty())
{
writeAlias(alias, settings);
if (frame.need_parens)
settings.ostr << ')';
}
}
}
void ASTWithAlias::appendColumnName(WriteBuffer & ostr) const
{
if (prefer_alias_to_column_name && !alias.empty())
writeString(alias, ostr);
else
appendColumnNameImpl(ostr);
}
void ASTWithAlias::appendColumnNameWithoutAlias(WriteBuffer & ostr) const
{
appendColumnNameImpl(ostr);
}
}
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