DESCRIBE FUNCTION xpath ;
DESCRIBE FUNCTION EXTENDED xpath ;
SELECT xpath ('b1b2b3c1c2', 'a/text()') FROM src LIMIT 1 ;
SELECT xpath ('b1b2b3c1c2', 'a/*/text()') FROM src LIMIT 1 ;
SELECT xpath ('b1b2b3c1c2', 'a/b/text()') FROM src LIMIT 1 ;
SELECT xpath ('b1b2b3c1c2', 'a/c/text()') FROM src LIMIT 1 ;
SELECT xpath ('b1b2b3c1c2', 'a/*[@class="bb"]/text()') FROM src LIMIT 1 ;