Red > Green > Refactor > Red

cycle is based on desire

return value of IN predicate ; sql

related to

NOT IN ; sql - Red > Green > Refactor > Red

snippet from reference

>>-+-expression1--+-----+--IN--+-(--fullselect1--)---------+-+-><
   |              '-NOT-'      |    .-,---------------.    | |   
   |                           |    V                 |    | |   
   |                           +-(------expression2---+--)-+ |   
   |                           '---expression3-------------' |   
   '-row-value-expression--+-----+--IN--(--fullselect2--)----'   
                           '-NOT-'
When the operator is IN, the result of the predicate is:
  True if at least one row returned from the fullselect2 is
  equal to the row-value-expression.
  False if the result of fullselect2 is empty
  or if no row returned from
  the fullselect2 is equal to the row-value-expression.
  Otherwise, unknown
  (that is, if the comparison of row-value-expression to
  the row returned from fullselect2 evaluates to unknown
  because of
  a null value for at least one row returned from fullselect2
  and no row returned from fullselect2
  is equal to the row-value-expression).
Examples
   DEPTNO IN ('D01', 'B01', 'C01');
   EMPNO IN(SELECT EMPNO FROM EMPLOYEE WHERE WORKDEPT = 'E11');

reference

IBM Knowledge Center