Re: Row pattern recognition

Hi Vik and Champion,

I think the current RPR patch is not quite correct in handling
count(*).

(using slightly modified version of Vik's example query)

SELECT v.a, count(*) OVER w
FROM (VALUES ('A'),('B'),('B'),('C')) AS v (a)
WINDOW w AS (
  ORDER BY v.a
  ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
  PATTERN (B+)
  DEFINE B AS a = 'B'
)
 a | count 
---+-------
 A |     0
 B |     2
 B |      
 C |     0
(4 rows)

Here row 3 is skipped because the pattern B matches row 2 and 3. In
this case I think cont(*) should return 0 rathern than NULL for row 3.

What do you think?

Best reagards,
--
Tatsuo Ishii
SRA OSS LLC
English: http://www.sraoss.co.jp/index_en/
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