Class RexFieldAccess

  • public class RexFieldAccess
    extends RexNode
    Access to a field of a row-expression.

    You might expect to use a RexFieldAccess to access columns of relational tables, for example, the expression emp.empno in the query

    SELECT emp.empno FROM emp

    but there is a specialized expression RexInputRef for this purpose. So in practice, RexFieldAccess is usually used to access fields of correlating variables, for example the expression emp.deptno in

    SELECT ename
     FROM dept
         SELECT NULL
         FROM emp
         WHERE emp.deptno = dept.deptno
         AND gender = 'F')