org.eigenbase.sql.fun
Class SqlExtractFunction

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

public class SqlExtractFunction
extends SqlFunction

The SQL EXTRACT operator. Extracts a specified field value from a DATETIME or an INTERVAL. E.g.
EXTRACT(HOUR FROM INTERVAL '364 23:59:59') returns 23

Version:

$Id: //open/dev/farrago/src/org/eigenbase/sql/fun/SqlExtractFunction.java#9 $

Author:

Wael Chatila

Field Summary

Fields inherited from class org.eigenbase.sql.SqlOperator

MaxPrec, NL

Constructor Summary

SqlExtractFunction()

Method Summary

String	getSignatureTemplate(int operandsCount) Returns a template describing how the operator signature is to be built.
void	unparse(SqlWriter writer, SqlNode[] operands, int leftPrec, int rightPrec) Writes a SQL representation of a call to this operator to a writer, including parentheses if the operators on either side are of greater precedence.

Methods inherited from class org.eigenbase.sql.SqlFunction

deriveType, getFunctionType, getNameAsId, getParamTypes, getSqlIdentifier, getSyntax, isQuantifierAllowed, 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, hashCode, inferReturnType, inferReturnType, isAggregator, isDeterministic, isDynamicFunction, isName, leftPrec, preValidateCall, requiresDecimalExpansion, rewriteCall, rightPrec, toString, unparseListClause, unparseListClause, validateOperands

Methods inherited from class java.lang.Object

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

Constructor Detail

SqlExtractFunction

public SqlExtractFunction()

Method Detail

getSignatureTemplate

public String getSignatureTemplate(int operandsCount)

Description copied from class: SqlOperator

Returns a template describing how the operator signature is to be built. E.g for the binary + operator the template looks like "{1} {0} {2}" {0} is the operator, subsequent numbers are operands.

Overrides:

getSignatureTemplate in class SqlOperator

Parameters:

operandsCount - is used with functions that can take a variable number of operands

Returns:

signature template, or null to indicate that a default template will suffice

unparse

public void unparse(SqlWriter writer,
                    SqlNode[] operands,
                    int leftPrec,
                    int rightPrec)

Description copied from class: SqlOperator

Writes a SQL representation of a call to this operator to a writer, including parentheses if the operators on either side are of greater precedence.

The default implementation of this method delegates to SqlSyntax.unparse(org.eigenbase.sql.SqlWriter, org.eigenbase.sql.SqlOperator, org.eigenbase.sql.SqlNode[], int, int).

Overrides:

unparse in class SqlFunction