CAST(NULL as ...)is considered to be a NULL literal but not
CAST(CAST(NULL as ...) AS ...)
Nested Class Summary
Method SummaryModifier and TypeMethodDescription
(SqlCallBinding callBinding, SqlNode node, int iFormalOperand, boolean throwOnFailure)Checks the type of a single operand against a particular ordinal position within a formal operator signature.Returns a string describing the allowed formal signatures of a call, e.g.
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface org.apache.calcite.sql.type.SqlOperandTypeChecker
and, getConsistency, isFixedParameters, isOptional, or, typeInference, withGenerator
checkSingleOperandTypepublic boolean checkSingleOperandType
(SqlCallBinding callBinding, SqlNode node, int iFormalOperand, boolean throwOnFailure)Description copied from interface:
SqlSingleOperandTypeCheckerChecks the type of a single operand against a particular ordinal position within a formal operator signature. Note that the actual ordinal position of the operand being checked may be different from the position of the formal operand.
For example, when validating the actual call
C(X, Y, Z)
the strategy for validating the operand Z might involve checking its type against the formal signature OP(W). In this case,
iFormalOperandwould be zero, even though the position of Z within call C is two.
Caution that we could not(shouldn't) implement implicit type coercion for this checker, implicit type coercion has side effect(modify the AST), if this single operand checker is subsumed in a composite rule(OR or AND), we can not make any side effect if we can not make sure that all the single operands type check are passed(with type coercion). But there is an exception: only if the call has just one operand, for this case, use
- Specified by:
callBinding- description of the call being checked; this is only provided for context when throwing an exception; the implementation should NOT examine the operands of the call as part of the check
node- the actual operand to be checked
iFormalOperand- the 0-based formal operand ordinal
throwOnFailure- whether to throw an exception if check fails (otherwise returns false in that case)
- whether check succeeded
getAllowedSignaturesDescription copied from interface:
SqlOperandTypeCheckerReturns a string describing the allowed formal signatures of a call, e.g. "SUBSTR(VARCHAR, INTEGER, INTEGER)".