Each record gets a date value that is one day less than the previous record date

How can I use SQL to update a column in a table, where each record gets a date value that is one day less than the previous record's date, in a loop based on record IDs?

loop with id and fetch all records and update date value today -1 for first record and again take this date and -1 update for next record id?

Got it! You want to update the date values of a column in a loop, where each record gets the date of the previous record decremented by one day. Here's how you can accomplish this using a cursor:

```sql server query

DECLARE @CurrentDate DATE

DECLARE @ID INT

-- Initialize the current date with today's date minus one day

SET @CurrentDate = DATEADD(DAY, -1, GETDATE())

DECLARE cursor_name CURSOR FOR

SELECT ID

FROM YourTableName

-- Add any condition here if needed

ORDER BY ID

OPEN cursor_name

FETCH NEXT FROM cursor_name INTO @ID

WHILE @@FETCH_STATUS = 0

BEGIN

    -- Update the date column for the current record

    UPDATE YourTableName

    SET YourDateColumn = @CurrentDate

    WHERE ID = @ID

    -- Decrement the current date by one day for the next iteration

    SET @CurrentDate = DATEADD(DAY, -1, @CurrentDate)

    -- Fetch the next record

    FETCH NEXT FROM cursor_name INTO @ID

END

CLOSE cursor_name

DEALLOCATE cursor_name

```

This script first initializes `@CurrentDate` with today's date minus one day. Then, it fetches each record one by one based on the specified conditions, updates the date column with `@CurrentDate`, decrements `@CurrentDate` by one day, and repeats the process for the next record until all records have been processed. Adjust the column name (`YourDateColumn`) and table name (`YourTableName`) as needed.