XPath expressions for filtering output

You can use an XPath expression to filter the XML output returned by a common SQL API stored procedure.

To filter the output, specify a valid XPath query string in the xml_filter parameter of the procedure. The following restrictions apply to the XPath expression that you specify:

• The XPath expression must reference a single value.
• The XPath expression must always be absolute from the root node. For example, the following path expressions are allowed: /, nodename, ., and ... The following expressions are not allowed: // and @
• The only predicates allowed are [path='value'] and [n].
• The only axis allowed is following-sibling.
• The XPath expression must end with one of the following, and, if necessary, be appended with the predicate [1]: following-sibling::string, following-sibling:: data, following-sibling::date, following-sibling::real, or following-sibling::integer.
• Unless the axis is found at the end of the XPath expression, it must be followed by a ::dict, ::string, ::data, ::date, ::real, or ::integer, and if necessary, be appended with the predicate [1].
• The only supported XPath operator is =.
• The XPath expression cannot contain a function, namespace, processing instruction, or comment.

For better control over processing the XML document returned in the xml_output parameter, you can use the XMLPARSE function available with Db2® pureXML®.

 /plist/dict/key[.='Data Server Product Version']following-sibling::string[1]