| Element_ID |   Element  | Transaction_Date | Transaction_Quantity | Total_Inventory |
|:----------:|:----------:|:----------------:|:--------------------:|:---------------:|
|    MO301   | Make_Order |     1/1/2019     |           1          |        1        |
|    MO302   | Make_Order |     1/3/2019     |           1          |        2        |
|    SO105   |    Sale    |     2/1/2019     |          -1          |        1        |
|    SO106   |    Sale    |     2/1/2019     |          -1          |        0        |
|    MO323   | Make_Order |     2/2/2019     |           1          |        1        |
|    SO107   |    Sale    |     2/4/2019     |          -1          |        0        |
|    SO191   |    Sale    |     2/5/2019     |          -1          |        -1       |
|    SO123   |    Sale    |     2/6/2019     |          -1          |        -2       |
|    SO166   |    Sale    |     3/1/2019     |          -1          |        -3       |
|    SO603   |    Sale    |     3/2/2019     |          -1          |        -4       |
|    MO400   | Make_Order |     3/15/2019    |           1          |        -3       |
|    MO459   | Make_Order |     3/15/2019    |           1          |        -2       |
|    MO460   | Make_Order |     3/18/2019    |           1          |        -1       |
|    MO491   | Make_Order |     3/19/2019    |           1          |        0        |

| Element_ID |   Element  | Transaction_Date | Transaction_Quantity | Total_Inventory | Replenishment | Replenishment_Date |
    |:----------:|:----------:|:----------------:|:--------------------:|:---------------:|:-------------:|:------------------:|
    |    MO301   | Make_Order |     1/1/2019     |           1          |        1        |      NULL     |        NULL        |
    |    MO302   | Make_Order |     1/3/2019     |           1          |        2        |      NULL     |        NULL        |
    |    SO105   |    Sale    |     2/1/2019     |          -1          |        1        |     MO301     |      1/1/2019      |
    |    SO106   |    Sale    |     2/1/2019     |          -1          |        0        |     MO302     |      1/3/2019      |
    |    MO323   | Make_Order |     2/2/2019     |           1          |        1        |      NULL     |        NULL        |
    |    SO107   |    Sale    |     2/4/2019     |          -1          |        0        |     MO323     |      2/2/2019      |
    |    SO191   |    Sale    |     2/5/2019     |          -1          |        -1       |     MO400     |      3/15/2019     |
    |    SO123   |    Sale    |     2/6/2019     |          -1          |        -2       |     MO459     |      3/15/2019     |
    |    SO166   |    Sale    |     3/1/2019     |          -1          |        -3       |     MO460     |      3/18/2019     |
    |    SO603   |    Sale    |     3/2/2019     |          -1          |        -4       |     MO491     |      3/19/2019     |
    |    MO400   | Make_Order |     3/15/2019    |           1          |        -3       |      NULL     |        NULL        |
    |    MO459   | Make_Order |     3/15/2019    |           1          |        -2       |      NULL     |        NULL        |
    |    MO460   | Make_Order |     3/18/2019    |           1          |        -1       |      NULL     |        NULL        |
    |    MO491   | Make_Order |     3/19/2019    |           1          |        0        |      NULL     |        NULL        |

for curr in transaction_quantity:
    if curr < 0:
        find the "soonest" positive value (even if that value occurred before the date of the curr transaction)
        fill in data from that
    else:
        next

/****** WiP Script  ******/
SELECT
    [jerry].[dbo].[purchases_new].*,
    CASE WHEN Transaction_Quantity < 0 THEN -- (SELECT Element_ID FROM the_current_row WHERE transaction_quantity > 0)
    ELSE NULL AS "Replenishment",
    -- (SELECT Transaction_Date FROM [jerry].[dbo].[purchases_new] WHERE Element_ID
    -- Not sure how to grab the correct date of the element id from the column before
FROM
    [jerry].[dbo].[purchases_new]