MATCH_ID

Returns a successful pattern match as an INTEGER value. The returned value is the ordinal position of a match within a partition.

Syntax

MATCH_ID()

Notes

Pattern matching functions must be used in MATCH Clause syntax; for example, if you call MATCH_ID() on its own, Vertica returns the following error message:

=> SELECT match_id();
ERROR:  query with pattern matching function match_id must include a MATCH clause

Example

This example uses the schema defined in Event Series Pattern Matching in Analyzing Data. For a more detailed example, see that topic.

The following statement analyzes users' browsing history on a site called website2.com and identifies patterns where the user reached website2.com from another Web site (Entry in the MATCH clause) and browsed to any number of other pages (Onsite) before making a purchase (Purchase). The query also outputs values for the MATCH_ID(), which represents a sequential number of the match.

SELECT uid,
       sid,
       ts,
       refurl,
       pageurl,
       action,
       match_id()
FROM clickstream_log
MATCH
  (PARTITION BY uid, sid ORDER BY ts
   DEFINE
     Entry    AS RefURL  NOT ILIKE '%website2.com%' AND PageURL ILIKE '%website2.com%',
     Onsite   AS PageURL ILIKE     '%website2.com%' AND Action='V',
     Purchase AS PageURL ILIKE     '%website2.com%' AND Action = 'P'
   PATTERN
     P AS (Entry Onsite* Purchase)
   ROWS MATCH FIRST EVENT); 

uid | sid |    ts    |        refurl        |       pageurl        | action | match_id
----+-----+----------+----------------------+----------------------+--------+------------
1   | 100 | 12:00:00 | website1.com         | website2.com/home    | V      |          1
1   | 100 | 12:01:00 | website2.com/home    | website2.com/floby   | V      |          2
1   | 100 | 12:02:00 | website2.com/floby   | website2.com/shamwow | V      |          3
1   | 100 | 12:03:00 | website2.com/shamwow | website2.com/buy     | P      |          4
2   | 100 | 12:10:00 | website1.com         | website2.com/home    | V      |          1
2   | 100 | 12:11:00 | website2.com/home    | website2.com/forks   | V      |          2
2   | 100 | 12:13:00 | website2.com/forks   | website2.com/buy     | P      |          3
(7 rows)

See Also