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sqlsql-serverdatetimeinsert

For each day between two dates, add a row with the same info but only that day in the start/end columns


I have a table, with types varchar, datetime, datetime:

NAME | START | END
Bob  | 10/30 | 11/2

What's a SQL query can I look up to find out how to make that table be?:

NAME | START | END
Bob  | 10/30 | 10/30
Bob  | 10/31 | 10/31
Bob  | 11/01 | 11/01
Bob  | 11/02 | 11/02

This is only ran once, and on a very small dataset. Optimization isn't necessary.


Solution

  • May be you need a Recursive CTE.

    CREATE TABLE #dates(NAME  VARCHAR(50),START DATETIME,[END] DATETIME)
    
    INSERT INTO #dates
    VALUES      ('Bob','2014-10-30','2014-11-02')
    
    DECLARE @maxdate DATETIME = (SELECT Max([end]) FROM   #dates);
    
    WITH cte
         AS (SELECT NAME,
                    START,
                    [END]
             FROM   #dates
             UNION ALL
             SELECT NAME,
                    Dateadd(day, 1, start),
                    Dateadd(day, 1, start)
             FROM   cte
             WHERE  start < @maxdate)
    SELECT *
    FROM   cte 
    

    OUTPUT :

    name    START       END
    ----    ----------  ----------
    Bob     2014-10-30  2014-10-30
    Bob     2014-10-31  2014-10-31
    Bob     2014-11-01  2014-11-01
    Bob     2014-11-02  2014-11-02