org.eigenbase.sql.fun
Class SqlExtractFunction

java.lang.Object
  extended by org.eigenbase.sql.SqlOperator
      extended by org.eigenbase.sql.SqlFunction
          extended by 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