duckdb::Expression Class Reference

The Expression class represents a bound Expression with a return type. More...

#include <duckdb.hpp>

Inheritance diagram for duckdb::Expression:

Collaboration diagram for duckdb::Expression:

Public Member Functions
	Expression (ExpressionType type, ExpressionClass expression_class, LogicalType return_type)
bool	IsAggregate () const override
	Returns true if this expression is an aggregate or not.
bool	IsWindow () const override
	Returns true if the expression has a window function or not.
bool	HasSubquery () const override
	Returns true if the query contains a subquery.
bool	IsScalar () const override
	Returns true if expression does not contain a group ref or col ref or parameter.
bool	HasParameter () const override
	Returns true if the expression has a parameter.
virtual bool	IsVolatile () const
virtual bool	IsConsistent () const
virtual bool	PropagatesNullValues () const
virtual bool	IsFoldable () const
virtual bool	CanThrow () const
hash_t	Hash () const override
bool	Equals (const BaseExpression &other) const override
	Returns true if this expression is equal to another expression.
virtual unique_ptr< Expression >	Copy () const =0
	Create a copy of this expression.
virtual void	Serialize (Serializer &serializer) const
Public Member Functions inherited from duckdb::BaseExpression
	BaseExpression (ExpressionType type, ExpressionClass expression_class)
	Create an Expression.
ExpressionClass	GetExpressionClass () const
	Returns the class of the expression.
ExpressionType	GetExpressionType () const
	Returns the type of the expression.
void	SetExpressionTypeUnsafe (ExpressionType new_type)
optional_idx	GetQueryLocation () const
	Returns the location in the query (if any)
void	SetQueryLocation (optional_idx location)
	Sets the location in the query.
bool	HasAlias () const
	Returns true if the expression has a non-empty alias.
const string &	GetAlias () const
	Returns the alias of the expression.
void	SetAlias (const string &alias_p)
	Sets the alias of the expression.
void	SetAlias (string &&alias_p)
	Sets the alias of the expression.
void	ClearAlias ()
	Clears the alias of the expression.
virtual string	GetName () const
	Get the name of the expression.
virtual string	ToString () const =0
	Convert the Expression to a String.
void	Print () const
	Print the expression to stdout.
bool	operator== (const BaseExpression &rhs) const
virtual void	Verify () const
template<class TARGET >
TARGET &	Cast ()
template<class TARGET >
const TARGET &	Cast () const

Static Public Member Functions
static bool	Equals (const Expression &left, const Expression &right)
static bool	Equals (const unique_ptr< Expression > &left, const unique_ptr< Expression > &right)
static bool	ListEquals (const vector< unique_ptr< Expression > > &left, const vector< unique_ptr< Expression > > &right)
static unique_ptr< Expression >	Deserialize (Deserializer &deserializer)
Static Public Member Functions inherited from duckdb::BaseExpression
static bool	Equals (const BaseExpression &left, const BaseExpression &right)

Public Attributes
LogicalType	return_type
	The return type of the expression.
unique_ptr< BaseStatistics >	verification_stats
	Expression statistics (if any) - ONLY USED FOR VERIFICATION.
Public Attributes inherited from duckdb::BaseExpression
ExpressionType	type
	Type of the expression.
ExpressionClass	expression_class
	The expression class of the node.
string	alias
	The alias of the expression,.
optional_idx	query_location
	The location in the query (if any)

Protected Member Functions
void	CopyProperties (const Expression &other)

Detailed Description

The Expression class represents a bound Expression with a return type.

Member Function Documentation

IsAggregate()

bool duckdb::Expression::IsAggregate ( ) const

overridevirtual

Returns true if this expression is an aggregate or not.

Examples:

(1) SUM(a) + 1 – True

(2) a + 1 – False

Implements duckdb::BaseExpression.

IsWindow()

bool duckdb::Expression::IsWindow ( ) const

overridevirtual

Returns true if the expression has a window function or not.

Implements duckdb::BaseExpression.

HasSubquery()

bool duckdb::Expression::HasSubquery ( ) const

overridevirtual

Returns true if the query contains a subquery.

Implements duckdb::BaseExpression.

IsScalar()

bool duckdb::Expression::IsScalar ( ) const

overridevirtual

Returns true if expression does not contain a group ref or col ref or parameter.

Implements duckdb::BaseExpression.

HasParameter()

bool duckdb::Expression::HasParameter ( ) const

overridevirtual

Returns true if the expression has a parameter.

Implements duckdb::BaseExpression.

Hash()

hash_t duckdb::Expression::Hash ( ) const

overridevirtual

Creates a hash value of this expression. It is important that if two expressions are identical (i.e. Expression::Equals() returns true), that their hash value is identical as well.

Implements duckdb::BaseExpression.

Equals() [1/2]

bool duckdb::Expression::Equals ( const BaseExpression &  other ) const

inlineoverridevirtual

Returns true if this expression is equal to another expression.

Reimplemented from duckdb::BaseExpression.

                                                            {
        if (!BaseExpression::Equals(other)) {
            return false;
        }
        return return_type == reinterpret_cast<const Expression &>(other).return_type;
    }

Here is the call graph for this function:

Equals() [2/2]

static bool duckdb::Expression::Equals ( const Expression &  left, const Expression &  right  )

inlinestatic

                                                                        {
        return left.Equals(right);
    }

Copy()

virtual unique_ptr< Expression > duckdb::Expression::Copy ( ) const

pure virtual

Create a copy of this expression.

Implemented in duckdb::BoundLambdaExpression, duckdb::BoundColumnRefExpression, duckdb::BoundReferenceExpression, duckdb::BoundConstantExpression, duckdb::BoundCastExpression, and duckdb::BoundFunctionExpression.

CopyProperties()

void duckdb::Expression::CopyProperties ( const Expression &  other )

inlineprotected

Copy base Expression properties from another expression to this one, used in Copy method

                                                 {
        type = other.type;
        expression_class = other.expression_class;
        alias = other.alias;
        return_type = other.return_type;
        query_location = other.query_location;
    }

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The documentation for this class was generated from the following file:

• external/duckdb/duckdb.hpp