>Sir I have this data (MS SQLSERVER 2008 TABLE)
>
>

>CREATE CURSOR junk(date t,sno n(3))
>SET DATE YMD
>SET CENTURY on
>
>INSERT INTO junk values({^2019-01-01 01:11:28.000},0)
>INSERT INTO junk values({^2019-01-01 03:21:23.000},0)
>INSERT INTO junk values({^2019-01-02 05:31:22.000},0)
>INSERT INTO junk values({^2019-01-02 15:41:27.000},0)
>INSERT INTO junk values({^2019-01-04 17:51:29.000},0)
>INSERT INTO junk values({^2019-01-04 21:51:19.000},0)
>INSERT INTO junk values({^2019-01-05 02:31:36.000},0)
>INSERT INTO junk values({^2019-01-08 05:21:48.000},0)
>INSERT INTO junk values({^2019-01-08 00:31:59.000},0)
>INSERT INTO junk values({^2019-01-08 18:41:35.000},0)
>INSERT INTO junk values({^2019-01-09 10:11:11.000},0)
>brow
>

>
>I want to UPDATE sno column like this
>
>
>
>Sno changes when date sequence is changed.
>No changes in previous sno if date is going in sequence (no missed date)
>
>Please

I have done this previously, and it involves selecting dates + 1 into a field, and searching for those in the original set, and as long as they do not exist, you keep iterating to find all of the dates that don't exist.

CREATE CURSOR junk(tDatetime t,sno n(3))
SET DATE YMD
SET CENTURY on

INSERT INTO junk values({^2019-01-01 01:11:28.000},0)
INSERT INTO junk values({^2019-01-01 03:21:23.000},0)
INSERT INTO junk values({^2019-01-02 05:31:22.000},0)
INSERT INTO junk values({^2019-01-02 15:41:27.000},0)
INSERT INTO junk values({^2019-01-04 17:51:29.000},0)
INSERT INTO junk values({^2019-01-04 21:51:19.000},0)
INSERT INTO junk values({^2019-01-05 02:31:36.000},0)
INSERT INTO junk values({^2019-01-08 05:21:48.000},0)
INSERT INTO junk values({^2019-01-08 00:31:59.000},0)
INSERT INTO junk values({^2019-01-08 18:41:35.000},0)
INSERT INTO junk values({^2019-01-09 10:11:11.000},0)

CREATE CURSOR c_missing (dDate d)

SELECT MAX(TTOD(tDatetime)) as dMax ;
    FROM junk ;
    INTO CURSOR c_range

SELECT TTOD(tDatetime)+1 AS dDate ;
    FROM junk ;
    WHERE TTOD(tDatetime)+1 < c_range.dMax AND TTOD(tDatetime)+1 NOT IN (SELECT TTOD(tDatetime) FROM junk) ;
    INTO CURSOR c_miss

IF USED("c_miss")
    DO WHILE _tally > 0
        SELECT c_missing
        APPEND FROM (DBF("c_miss"))

        SELECT dDate+1 AS dDate ;
            FROM c_miss ;
            WHERE dDate+1 < c_range.dMax AND dDate+1 NOT IN (SELECT TTOD(tDatetime) FROM junk) ;
            INTO CURSOR c_miss
    ENDDO
ENDIF

SELECT c_missing
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