How to use EQUIV operator in a query?

Question

i want to list products whose names like 'Windows XP' or 'WindowsXP', following is my query:
select * from product
where contains(product_name,'Windows XP = WindowsXP',1) > 0
but this query only return the products whose name contain 'Windows XP'. the result is something likes
select * from product
where contains(product_name,'Windows (XP = WindowsXP)',1) > 0
so i modified it to :
select * from product
where contains(product_name,'(Windows XP) = (WindowsXP)',1) > 0
it's error
Error report:
SQL Error: ORA-29902: error in executing ODCIIndexStart() routine
ORA-20000: Oracle Text error:
DRG-50900: text query parser error on line 1, column 26
DRG-50921: EQUIV operand not a word or another EQUIV expression
29902. 00000 - "error in executing ODCIIndexStart() routine"
*Cause:    The execution of ODCIIndexStart routine caused an error.
*Action:   Examine the error messages produced by the indextype code and
take appropriate action.

Answer 1

Equiv only works for individual terms. Since there is a space between Windows and XP, they are two terms. You can use synonyms for phrases containing multiple terms, as shown below.
SCOTT@orcl_11g> CREATE TABLE product (product_name  VARCHAR2 (30))
  2  /
Table created.
SCOTT@orcl_11g> INSERT ALL
  2  INTO product VALUES ('Windows XP')
  3  INTO product VALUES ('WindowsXP')
  4  INTO product VALUES ('Unix')
  5  SELECT * FROM DUAL
  6  /
3 rows created.
SCOTT@orcl_11g> BEGIN
  2    CTX_THES.CREATE_THESAURUS ('name_thes');
  3    CTX_THES.CREATE_RELATION ('name_thes', 'Windows XP', 'SYN', 'WindowsXP');
  4  END;
  5  /
PL/SQL procedure successfully completed.
SCOTT@orcl_11g> CREATE INDEX product_name_idx ON product (product_name)
  2  INDEXTYPE IS CTXSYS.CONTEXT
  3  /
Index created.
SCOTT@orcl_11g> SELECT * FROM product
  2  WHERE  CONTAINS (product_name, 'SYN (Windows XP, name_thes)') > 0
  3  /
PRODUCT_NAME
Windows XP
WindowsXP
SCOTT@orcl_11g> SELECT * FROM product
  2  WHERE  CONTAINS (product_name, 'SYN (WindowsXP, name_thes)') > 0
  3  /
PRODUCT_NAME
Windows XP
WindowsXP
SCOTT@orcl_11g>