14.9.5.11 operator -
operator- subtracts the supplied value, from the supplied OracleTimeStampLTZ value, and returns a new OracleTimeStampLTZ structure. 
                  
Overload List:
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                        operator - (OracleTimeStampLTZ, OracleIntervalDS) This static operator subtracts the supplied OracleIntervalDSvalue, from the suppliedOracleTimeStampLTZvalue, and return a newOracleTimeStampLTZstructure.
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                        operator - (OracleTimeStampLTZ, OracleIntervalYM) This static operator subtracts the supplied OracleIntervalYMvalue, from the suppliedOracleTimeStampLTZvalue, and returns a newOracleTimeStampLTZstructure.
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                        operator - (OracleTimeStampLTZ, TimeSpan) This static operator subtracts the supplied TimeSpanvalue, from the suppliedOracleTimeStampLTZvalue, and returns a newOracleTimeStampLTZstructure.