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Semi-structured Data Functions (Extraction)
XMLGET¶
Extracts an XML element object (often referred to as simply a “tag”) from a content of outer XML element object by the name of the tag and its instance number (counting from 0):
If any argument of XMLGET is NULL, the result is NULL.
If the tag instance is not found, the result is similarly NULL.
Syntax¶
XMLGET( <type> , <tag_name> , [ <instance_num> ] )
Usage Notes¶
instance_num
can be omitted, in which case the default value 0 is used.The result of XMLGET is not the content of the tag, but the tag itself (an object):
To extract attribute values, use
GET(tag, '@attrname')
.To extract the content, use
GET(tag, '$')
.To extract the tag name, use
GET(tag, '@')
.
Positions of the inner tags in the content can be obtained by using
GET(tag, 'inner-tag-name')
; if the content contains multiple elements, it will be represented as an array.
Examples¶
SELECT GET(XMLGET(xml, 'dt', 2), '$') as "Term",
GET(XMLGET(xml, 'dd', 2), '$') as "Definition"
FROM dictionary;