DESCRIBE FUNCTION xpath_string ;
DESCRIBE FUNCTION EXTENDED xpath_string ;
SELECT xpath_string ('bbcc', 'a') FROM src LIMIT 1 ;
SELECT xpath_string ('bbcc', 'a/b') FROM src LIMIT 1 ;
SELECT xpath_string ('bbcc', 'a/c') FROM src LIMIT 1 ;
SELECT xpath_string ('bbcc', 'a/d') FROM src LIMIT 1 ;
SELECT xpath_string ('b1b2', '//b') FROM src LIMIT 1 ;
SELECT xpath_string ('b1b2', 'a/b[1]') FROM src LIMIT 1 ;
SELECT xpath_string ('b1b2', 'a/b[2]') FROM src LIMIT 1 ;
SELECT xpath_string ('b1b2', 'a/b[@id="b_2"]') FROM src LIMIT 1 ;