Defines the set of standard SQL row-level functions and operators.

The standard set of row-level functions and operators are declared in class SqlStdOperatorTable. Anonymous inner classes within that table are allowed only for specifying an operator's test function; if other custom code is needed for an operator, it should be implemented in a top-level class within this package instead. Operators which are not row-level (e.g. select and join) should be defined in package org.apache.calcite.sql instead.