Sql-server – How to add/update a column with an incremented value and reset said value based on another column in SQL

alter-tablesql servert-sqltemporary-tablesupdate

I am stumped, I have searched and researched until my browser tabs no longer show the close button ("X") until you hover over them.
I tried rewriting the search term over and over but I guess I do not know exactly what to ask so I apologise if this has been answered already.

I am trying to figure out how I can add an INT column to a table which starts at and increments by 1 (let's call this field version) based on another columns value (which we shall call case_id) IF that value is the same as the previously iterated row – in the case it is NOT the same, then the version value should reset to 1.

I have tried to figure it out by either updating a temp table I create, or adding the value during the SELECT INTO statement.

The purpose of this table is to store a record of the historic updates to a case, identified by the case_id column, with this version value in the same order as the modify timestamp.

Consider this table structure as an example of the source data:

---------------------------------
| case_id | modify_time         |
---------------------------------
| 1       | 2015-05-01 11:12:13 |
| 1       | 2015-05-02 12:13:14 |
| 1       | 2015-05-03 13:14:15 |
| 2       | 2015-05-01 11:12:13 |
| 2       | 2015-05-01 12:13:14 |
| 3       | 2015-05-02 11:12:13 |
---------------------------------

Consider this as an example of exactly what I want to achieve as the end result:

-------------------------------------------
| case_id | modify_time         | version |
-------------------------------------------
| 1       | 2015-05-01 11:12:13 | 1       |
| 1       | 2015-05-02 12:13:14 | 2       |
| 1       | 2015-05-03 13:14:15 | 3       |
| 2       | 2015-05-01 11:12:13 | 1       |
| 2       | 2015-05-01 12:13:14 | 2       |
| 3       | 2015-05-02 11:12:13 | 1       |
-------------------------------------------

As you can see, I need to add the version (INT) column and insert an incremented value based on the modify_time (ascending order) which will reset when the case_id value changes.

I have tried a few things I have stumbled on during my searches, but nothing I have come across has been able to help me figure this out.

I guess this is just a little too advanced for me.. 🙁
This is on SQL Server 2012 and I am not afraid to try anything no matter how advanced as I can only learn from this exercise.

Thank you for taking the time to view my question and thank you in advance if you can help me out here.
Cheers.

Best Answer

You can maintain this column easily:

;WITH x AS 
(
  SELECT case_id, modify_time, version, 
    rn = ROW_NUMBER() OVER (PARTITION BY case_id ORDER BY modify_date)
  FROM dbo.source_table
)
UPDATE x SET version = rn WHERE version <> rn;

But since you could also generate that version column on the fly every time you need to query (maybe it could be in a view), I don't see any benefit of storing the output or even having a version column in the table, since you are potentially going to be updating it more often than you read it (you will have to update entire ranges or even the entire table every time any rows are changed or added).

If you are moving data from one system to another, or one table to another, you still don't need this column to exist in the source table, and you don't need a temporary table to store this column either:

INSERT dbo.target_table(case_id, modify_time, version)
SELECT case_id, modify_time, version = ROW_NUMBER() OVER
  (PARTITION BY case_id ORDER BY modify_date)
FROM dbo.source_table;

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Sql-server – Getting current date as part of an Stored Procedure

1) I'm not going to argue database design, since it seems that it's already in place.

2) Looking at the code, I have to presume that StartOnCallDate, StartOnCallTime, and Duration are Integers. If you're trying to do that with DATETIME, then there are other issues to deal with.

To answer your question...

First off, the math in your where clause is still including the time (hours and seconds). So this stuff:

DATEADD(ms , 0 - DATEPART(ms , GETDATE()) ,
            DATEADD(s , 0 - DATEPART(s , GETDATE()) , GETDATE()))

Gives this result:

SELECT DATEADD(ms , 0 - DATEPART(ms , GETDATE()) ,
        DATEADD(s , 0 - DATEPART(s , GETDATE()) , GETDATE()))
-----------------------
2011-08-12 15:35:00.000

So, when you compare DATEADD(DAY, mOnCallAdd.StartOnCallDate, '12/31/1899') to that mess above, it will almost never be equal. That's because when you use DATEADD(DAY...) to that hard-coded date, you will only end up with values that are days:

SELECT DATEADD(DAY, 40800, '12/31/1899')
-----------------------
2011-09-15 00:00:00.000

To drop the hours and seconds, you could do a bunch more DATEADD stuff, or you could just do something like this:

(SQL Server 2008):
CONVERT (date, GETDATE())

(SQL Server 2005/2008 options):
CAST(CONVERT(VARCHAR(10), getdate(), 101) AS DATETIME)
CAST(FLOOR(CAST(GETDATE() AS DECIMAL(12, 5))) AS DATETIME)

Those will get you JUST the date. If you throw one of those into your where clause, it will allow you to filter the data, showing you all values that match the current DAY (anything that is going to occur today):

WHERE DATEADD(DAY, mOnCallAdd.StartOnCallDate, '12/31/1899')= 
    CAST(CONVERT(VARCHAR(10), getdate(), 101) AS DATETIME) AND
    mOnCallAdd.SchedName = 'arc im'

To give you an idea of the values you are comparing, pull each of those out (with sample data) into a select statement:

SELECT 
    DATEADD(DAY, 40766, '12/31/1899'), 
    CAST(CONVERT(VARCHAR(10), getdate(), 101) AS DATETIME)
----------------------- -----------------------
2011-08-12 00:00:00.000 2011-08-12 00:00:00.000

Now, to filter out anything that might have already passed, you want to add a condition to your WHERE clause that checks the ending time to determine if that is earlier that the current time.

 DATEADD(MINUTE, mOnCallAdd.duration,
         DATEADD(MINUTE, mOnCallAdd.StartOnCallTime,
         DATEADD(DAY, mOnCallAdd.StartOnCallDate, '12/31/1899'))) > GetDate()

This makes the entire where clause:

WHERE DATEADD(DAY, mOnCallAdd.StartOnCallDate, '12/31/1899')= 
        CAST(CONVERT(VARCHAR(10), getdate(), 111) AS DATETIME) AND
     DATEADD(MINUTE, mOnCallAdd.duration,
             DATEADD(MINUTE, mOnCallAdd.StartOnCallTime,
             DATEADD(DAY, mOnCallAdd.StartOnCallDate, '12/31/1899'))) > GetDate() AND
     mOnCallAdd.SchedName = 'arc im'

EDIT:

If you only want items to show up that are currently happening, you need to qualify on both your end time (as above) and your start time. To qualify your start time, you need to get your start time and make sure that the current time is greater than or equal to the current time:

DATEADD(MINUTE, mOnCallAdd.StartOnCallTime,
        DATEADD(DAY, mOnCallAdd.StartOnCallDate, '12/31/1899')) <= GetDate()

This makes the entire WHERE clause:

WHERE DATEADD(DAY, mOnCallAdd.StartOnCallDate, '12/31/1899')= 
        CAST(CONVERT(VARCHAR(10), getdate(), 111) AS DATETIME) AND
     DATEADD(MINUTE, mOnCallAdd.duration,
             DATEADD(MINUTE, mOnCallAdd.StartOnCallTime,
             DATEADD(DAY, mOnCallAdd.StartOnCallDate, '12/31/1899'))) > GetDate() AND
     DATEADD(MINUTE, mOnCallAdd.StartOnCallTime,
             DATEADD(DAY, mOnCallAdd.StartOnCallDate, '12/31/1899')) <= GetDate() AND
     mOnCallAdd.SchedName = 'arc im'

Sql-server – Update one column based on count of records of grouped value in another column

CREATE TABLE TABLE_ITEMS (
    serial_num int null,
    item_group int null
 )
 GO

INSERT INTO TABLE_ITEMS
VALUES 
(0,1), (1,1), (2,1),(3,1) ,(4,1) ,(0,2) ,(1,2), (2,2), (3,2), (4,2), (5,2), (0,3) ,(1,3) ,(2,3)
GO

SELECT 
    Item_group, 
    ROW_NUMBER() OVER (PARTITION BY item_group order by item_group) AS AddNum 
INTO #NewSerials
from TABLE_ITEMS 
WHERE serial_num <> 0

SELECT * FROM TABLE_ITEMS

;WITH CTE AS 
(SELECT MAX(addnum) as addnum, item_group from #NewSerials group by item_group)
UPDATE ti
    SET ti.serial_num = CTE.AddNum
FROM TABLE_ITEMS ti
JOIN CTE ON CTE.item_group = ti.item_group
WHERE ti.serial_num = 0

SELECT * FROM TABLE_ITEMS

5   1
1   1
2   1
3   1
4   1
6   2
1   2
2   2
3   2
4   2
5   2
3   3
1   3
2   3

Best Answer

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Sql-server – Getting current date as part of an Stored Procedure

Sql-server – Update one column based on count of records of grouped value in another column

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