org.eigenbase.sql.fun
Class SqlCoalesceFunction

java.lang.Object
  org.eigenbase.sql.SqlOperator
      org.eigenbase.sql.SqlFunction
          org.eigenbase.sql.fun.SqlCoalesceFunction

public class SqlCoalesceFunction
extends SqlFunction

The COALESCE function.

Version:

$Id: //open/dev/farrago/src/org/eigenbase/sql/fun/SqlCoalesceFunction.java#14 $

Author:

Wael Chatila

Field Summary

Fields inherited from class org.eigenbase.sql.SqlOperator

MaxPrec, NL

Constructor Summary

SqlCoalesceFunction()

Method Summary

SqlNode

rewriteCall(SqlValidator validator, SqlCall call) Rewrites a call to this operator.

Methods inherited from class org.eigenbase.sql.SqlFunction

deriveType, getFunctionType, getNameAsId, getParamTypes, getSqlIdentifier, getSyntax, isQuantifierAllowed, unparse, validateCall, validateQuantifier

Methods inherited from class org.eigenbase.sql.SqlOperator

acceptCall, acceptCall, adjustType, argumentMustBeScalar, checkOperandCount, checkOperandTypes, createCall, createCall, createCall, createCall, equals, getAllowedSignatures, getAllowedSignatures, getKind, getLeftPrec, getMonotonicity, getName, getOperandCountRange, getOperandTypeChecker, getOperandTypeInference, getReturnTypeInference, getRightPrec, getSignatureTemplate, hashCode, inferReturnType, inferReturnType, isAggregator, isDeterministic, isDynamicFunction, isName, leftPrec, preValidateCall, requiresDecimalExpansion, rightPrec, toString, unparseListClause, unparseListClause, validateOperands

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

SqlCoalesceFunction

public SqlCoalesceFunction()

Method Detail

rewriteCall

public SqlNode rewriteCall(SqlValidator validator,
                           SqlCall call)

Description copied from class: SqlOperator

Rewrites a call to this operator. Some operators are implemented as trivial rewrites (e.g. NULLIF becomes CASE). However, we don't do this at createCall time because we want to preserve the original SQL syntax as much as possible; instead, we do this before the call is validated (so the trivial operator doesn't need its own implementation of type derivation methods). The default implementation is to just return the original call without any rewrite.

Overrides:

rewriteCall in class SqlOperator

call - to be rewritten

Returns:

rewritten call