org.apache.calcite.sql.type

Interface SqlReturnTypeInference

All Known Implementing Classes:

CursorReturnTypeInference, ExplicitReturnTypeInference, MatchReturnTypeInference, OrdinalReturnTypeInference, SqlReturnTypeInferenceChain, SqlTypeTransformCascade, TableFunctionReturnTypeInference

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface SqlReturnTypeInference

Strategy interface to infer the type of an operator call from the type of the operands.

This interface is an example of the strategy pattern. This makes sense because many operators have similar, straightforward strategies, such as to take the type of the first operand.

See Also:

ReturnTypes

Method Summary

Modifier and Type	Method and Description
default SqlReturnTypeInference	andThen(SqlTypeTransform transform) Returns a return-type inference that applies this rule then a transform.
@Nullable RelDataType	inferReturnType(SqlOperatorBinding opBinding) Infers the return type of a call to an SqlOperator.
default SqlReturnTypeInference	orElse(SqlReturnTypeInference transform) Returns a return-type inference that applies this rule then another rule, until one of them returns a not-null result.

Method Detail

inferReturnType

@Nullable RelDataType inferReturnType(SqlOperatorBinding opBinding)

Infers the return type of a call to an SqlOperator.

Parameters:

opBinding - description of operator binding

Returns:

inferred type; may be null

andThen

default SqlReturnTypeInference andThen(SqlTypeTransform transform)

Returns a return-type inference that applies this rule then a transform.

orElse

default SqlReturnTypeInference orElse(SqlReturnTypeInference transform)

Returns a return-type inference that applies this rule then another rule, until one of them returns a not-null result.