et_condition ::=

{
  { FIELDNAME |  range start : range end }
  { = | != } 
  { string | BLANKS | NULL } 
 |
  ( { FIELDNAME |  range start : range end } 
  { = | != } 
  { string | BLANKS | NULL } )
}
 

For information on how to read this syntax, see Appendix B.

End of description.