1

我想在原始行中添加一个标志，以指示何时找到匹配项。有没有更好的方法只使用 MATCH_RECOGNIZE 而不需要我在下面完成的 RIGHT JOIN？有 6 个匹配项，我想通过在 60 行的原始表中添加一个新列来标记这 6 个匹配项。

WITH match_results AS (
    SELECT *
    FROM Ticker 
    MATCH_RECOGNIZE (
     PARTITION BY symbol
     ORDER BY tstamp
     MEASURES 
      FIRST(down.tstamp) AS start_ts,
      LAST(DOWN.tstamp) AS bottom_ts,
      LAST(UP.tstamp) AS end_ts
     ONE ROW PER MATCH
     AFTER MATCH SKIP PAST LAST ROW
     PATTERN (STRT DOWN+ UP+)
     DEFINE
      DOWN AS price < PREV(price), 
      UP AS price > PREV(price)
    ) MR
    ORDER BY MR.symbol, MR.start_ts
)
SELECT * FROM match_results
RIGHT JOIN ticker 
ON match_results.SYMBOL = ticker.symbol
AND match_results.bottom_ts = ticker.TSTAMP;

这是示例数据：

CREATE TABLE ticker (SYMBOL VARCHAR2(10), tstamp DATE, price NUMBER);

BEGIN
INSERT INTO ticker VALUES('ACME', '01-Apr-11', 12);
INSERT INTO ticker VALUES('GLOBEX', '17-Apr-11', 8);
INSERT INTO ticker VALUES('GLOBEX', '01-Apr-11', 11);
INSERT INTO ticker VALUES('OSCORP', '20-Apr-11', 9);
INSERT INTO ticker VALUES('ACME', '02-Apr-11', 17);
INSERT INTO ticker VALUES('OSCORP', '19-Apr-11', 11);
INSERT INTO ticker VALUES('ACME', '03-Apr-11', 19);
INSERT INTO ticker VALUES('GLOBEX', '03-Apr-11', 13);
INSERT INTO ticker VALUES('OSCORP', '18-Apr-11', 12);
INSERT INTO ticker VALUES('GLOBEX', '02-Apr-11', 12);
INSERT INTO ticker VALUES('ACME', '04-Apr-11', 21);
INSERT INTO ticker VALUES('GLOBEX', '04-Apr-11', 12);
INSERT INTO ticker VALUES('OSCORP', '17-Apr-11', 14);
INSERT INTO ticker VALUES('OSCORP', '15-Apr-11', 12);
INSERT INTO ticker VALUES('OSCORP', '14-Apr-11', 15);
INSERT INTO ticker VALUES('OSCORP', '16-Apr-11', 16);
INSERT INTO ticker VALUES('ACME', '05-Apr-11', 25);
INSERT INTO ticker VALUES('GLOBEX', '05-Apr-11', 11);
INSERT INTO ticker VALUES('ACME', '06-Apr-11', 12);
INSERT INTO ticker VALUES('GLOBEX', '06-Apr-11', 10);
INSERT INTO ticker VALUES('ACME', '07-Apr-11', 15);
INSERT INTO ticker VALUES('GLOBEX', '07-Apr-11', 9);
INSERT INTO ticker VALUES('GLOBEX', '08-Apr-11', 8);
INSERT INTO ticker VALUES('ACME', '08-Apr-11', 20);
INSERT INTO ticker VALUES('OSCORP', '13-Apr-11', 11);
INSERT INTO ticker VALUES('ACME', '13-Apr-11', 25);
INSERT INTO ticker VALUES('ACME', '10-Apr-11', 25);
INSERT INTO ticker VALUES('ACME', '11-Apr-11', 19);
INSERT INTO ticker VALUES('ACME', '09-Apr-11', 24);
INSERT INTO ticker VALUES('GLOBEX', '09-Apr-11', 9);
INSERT INTO ticker VALUES('OSCORP', '12-Apr-11', 12);
INSERT INTO ticker VALUES('GLOBEX', '10-Apr-11', 9);
INSERT INTO ticker VALUES('OSCORP', '11-Apr-11', 15);
INSERT INTO ticker VALUES('GLOBEX', '11-Apr-11', 9);
INSERT INTO ticker VALUES('OSCORP', '10-Apr-11', 15);
INSERT INTO ticker VALUES('ACME', '12-Apr-11', 15);
INSERT INTO ticker VALUES('GLOBEX', '12-Apr-11', 9);
INSERT INTO ticker VALUES('OSCORP', '09-Apr-11', 16);
INSERT INTO ticker VALUES('GLOBEX', '13-Apr-11', 10);
INSERT INTO ticker VALUES('OSCORP', '08-Apr-11', 20);
INSERT INTO ticker VALUES('ACME', '14-Apr-11', 25);
INSERT INTO ticker VALUES('GLOBEX', '14-Apr-11', 11);
INSERT INTO ticker VALUES('OSCORP', '07-Apr-11', 17);
INSERT INTO ticker VALUES('OSCORP', '06-Apr-11', 20);
INSERT INTO ticker VALUES('ACME', '15-Apr-11', 14);
INSERT INTO ticker VALUES('GLOBEX', '15-Apr-11', 12);
INSERT INTO ticker VALUES('ACME', '17-Apr-11', 14);
INSERT INTO ticker VALUES('ACME', '16-Apr-11', 12);
INSERT INTO ticker VALUES('GLOBEX', '16-Apr-11', 11);
INSERT INTO ticker VALUES('OSCORP', '05-Apr-11', 17);
INSERT INTO ticker VALUES('ACME', '18-Apr-11', 24);
INSERT INTO ticker VALUES('GLOBEX', '18-Apr-11', 7);
INSERT INTO ticker VALUES('OSCORP', '04-Apr-11', 18);
INSERT INTO ticker VALUES('OSCORP', '03-Apr-11', 19);
INSERT INTO ticker VALUES('ACME', '19-Apr-11', 23);
INSERT INTO ticker VALUES('GLOBEX', '19-Apr-11', 5);
INSERT INTO ticker VALUES('OSCORP', '02-Apr-11', 22);
INSERT INTO ticker VALUES('ACME', '20-Apr-11', 22);
INSERT INTO ticker VALUES('GLOBEX', '20-Apr-11', 3);
INSERT INTO ticker VALUES('OSCORP', '01-Apr-11', 22);

commit;
END;

这是我的结果：

在此处输入图像描述

4

1 回答 1

2

你可以使用ALL ROWS PER MATCH SHOW EMPTY MATCHES：

SELECT *
FROM Ticker 
MATCH_RECOGNIZE (
 PARTITION BY symbol
 ORDER BY tstamp
 MEASURES 
  FIRST(down.tstamp) AS start_ts,
  LAST(DOWN.tstamp) AS bottom_ts,
  LAST(UP.tstamp) AS end_ts,
  CLASSIFIER() AS classifier
 ALL ROWS PER MATCH WITH UNMATCHED ROWS
 AFTER MATCH SKIP PAST LAST ROW
 PATTERN (STRT DOWN+ UP+)
 DEFINE
  DOWN AS price < PREV(price), 
  UP AS price > PREV(price)
) MR
ORDER BY MR.symbol, MR.start_ts;

db<>小提琴演示

于 2019-06-20T16:50:21.713 回答