org.apache.flink.table.expressions

接口 Expression

所有已知子接口:

ResolvedExpression

所有已知实现类:

AggregateExpression, CallExpression, FieldReferenceExpression, SqlCallExpression, TypeLiteralExpression, ValueLiteralExpression

@PublicEvolving
public interface Expression

General interface for all kinds of expressions.

Expressions represent a logical tree for producing a computation result. Every expression consists of zero, one, or more subexpressions. Expressions might be literal values, function calls, or field references.

Expressions are part of the API. They might be transformed multiple times within the API stack until they are fully ResolvedExpressions. Value types and output types are expressed as instances of DataType.

方法概要

限定符和类型	方法和说明
<R> R	accept(ExpressionVisitor<R> visitor)
String	asSummaryString() Returns a string that summarizes this expression for printing to a console.
List<Expression>	getChildren()

方法详细资料

asSummaryString

String asSummaryString()

Returns a string that summarizes this expression for printing to a console. An implementation might skip very specific properties.

返回:

summary string of this expression for debugging purposes

getChildren

List<Expression> getChildren()

accept

<R> R accept(ExpressionVisitor<R> visitor)