GROUP_DIGEST
returns an arbitrary value from the multiset passed to it.
GROUP_DIGEST
(in token varchar,
in delim varchar,
in maxlen integer,
in mode integer);
Description
GROUP_DIGEST is aggregate function that performs a string concatenation across
the values of an expression with a group. The order of the strings is not specified.
The separator character used in the concatenation may be given with the scalar
argument delimiter. The function is an extended version of sql:GROUP_CONCAT(), with
two more arguments: maxlen and mode.
Note: the "sql:" prefix is mandatory when this aggregate is used in SPARQL queries.
In SQL queries the prefix is "DB.DBA".
Parameters
token –
An item that should be added to a delimited list.
delim –
The delimeter character to be used in the concatenation.
maxlen –
The maximal allowed length of the result, in characters. Redundant values will be ignored.
If the last value does not fit in the "maxlen" entirely, then it can be truncated and "..." is
placed at the end of the resulting string.
mode –
Bitmask of properties. Right now only bit 1 is used and others are reserved. If the value
of the argument is 1 then duplicate values are ignored; value 0 will put duplicate values like
in case of sql:GROUP_CONCAT ().
Examples
Get all ?assets as a list with delimiters.
SQL>SPARQL
SELECT ?view (sql:GROUP_DIGEST (?path, ' ', 1000, 1)) as ?path_list
(sql:GROUP_DIGEST (?asset, ' ', 1000, 1)) as ?asset_list
FROM <http://mygraph.com>
WHERE
{
?view <viewPath> ?path ;
<viewContent> ?asset ;
<viewType> 'phyview'.
};