OPERATOR               REASON  
--------               ----------- 
OR                     Return  TRUE  when either one of conditions
                       is true  
AND                    Return  TRUE  only when both conditions
                       are true
NOT                    Return  TRUE  if  "not equal"
=                      Test for equality
!=                     Test for inequality 
^=                     Same as !=
<>                     Same as !=
<                      Less then
>                      Creater than
<=                     Less than or equal to
>=                     Creater than or equal to
in                     Equal to any member in parentless
not in                 Not equal to any member in parentless
between A and B        Greater than or equal to A and less than
                       or equal to B 
not  between A and B   Not greater than or equal to A and not 
                       less than  or equal to B 
like '%tin%'           Contains given text (e.g. 'tin')
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