Is there a way to write a row based condition in Left Join.
If some row not exists based on column condition, then it should take the next first row.
I have the structure below,
create table Report
(
id int,
name varchar(10)
)
create table ReportData
(
report_id int references report(id),
flag bit,
path varchar(50)
)
insert into Report values (1, 'a');
insert into Report values (2, 'b');
insert into Report values (3, 'c');
insert into ReportData values (1, 0, 'xx');
insert into ReportData values (2, 0, 'yy');
insert into ReportData values (2, 1, 'yy');
insert into ReportData values (3, 1, 'zz');
insert into ReportData values (3, 1, 'mm');
I need some output like
1 a 0 xx
2 b 0 yy
3 c 1 zz
You can use ROW_NUMBER for this:
;WITH ReportDate_Rn AS (
SELECT report_id, flag, path,
ROW_NUMBER() OVER (PARTITION BY report_id ORDER BY path) AS rn
FROM ReportDate
)
SELECT t1.id, t1.name, t2.flag, t2.path
FROM Report AS t1
JOIN ReportDate_Rn AS t2 ON t1.id = t2.report_id AND t2.rn = 1
The above query regards as first record of each report_id slice, the one having the alphabetically smallest path. You may amend the ORDER BY clause of the ROW_NUMBER() window function as you wish.
SELECT id,name,flag,path
FROM
(
SELECT Report.id,Report.name,ReportData.flag,ReportData.path,
row_number() over(partition by ReportData.report_id order by flag) as rownum
FROM Report
JOIN ReportData on Report.id = ReportData.report_id
) tmp
WHERE tmp.rownum=1
A simpler alternative to the left join, using rowid and rownum
SELECT id, name, flag, path
FROM report, reportdata
WHERE reportdata.rowid = (SELECT rowid
FROM reportdata
WHERE id = report_id
AND rownum = 1);
Without using row_numner() you can achieve this.
Have a look at this SQL Fiddle
select r.id, r.name, d.flag, d.path from report r
inner join reportdata d
on r.id = d.report_id group by d.report_id
PS: I wasn't believing the result - I was just building the query - haven't used d.report_id in the select clause and it worked. Will be updating this answer once I get the reason why this query worked :)
Use Partition BY:
declare #Report AS table
(
id int,
name varchar(10)
)
declare #ReportData AS table
(
report_id int ,
flag bit,
path varchar(50)
)
insert into #Report values (1, 'a');
insert into #Report values (2, 'b');
insert into #Report values (3, 'c');
insert into #ReportData values (1, 0, 'xx');
insert into #ReportData values (2, 0, 'yy');
insert into #ReportData values (2, 1, 'yy');
insert into #ReportData values (3, 1, 'zz');
insert into #ReportData values (3, 1, 'mm');
;WITH T AS
(
Select
R.id,
r.name,
RD.flag,
RD.path,
ROW_NUMBER () OVER(PARTITION BY R.id ORDER BY R.id) AS PartNo
FROM #Report R
LEFT JOIN #ReportData RD ON R.id=RD.report_id
)
SELECT
T.id,
T.name,
T.flag,
T.path
FROM T WHERE T.PartNo=1
Related
DECLARE #tmp1 TABLE (ItemCode INT, Item VARCHAR(30), Qty INT)
INSERT INTO #tmp1 (ItemCode, Item, Qty)
VALUES(1, 'Item1', 300),
(2, 'Item2', 500)
DECLARE #tmp2 TABLE (JobNo INT, ItemCode INT, Item VARCHAR(30), Qty INT)
INSERT INTO #tmp2 (JobNo, ItemCode, Item, Qty)
VALUES(1, 1, 'Item1', 150),
(2, 1, 'Item1', 150),
(3, 2, 'Item1', 50),
(4, 2, 'Item1', 75),
(5, 2, 'Item1', 125),
(6, 2, 'Item1', 100)
;WITH MyCTE AS
(
SELECT t1.ItemCode, t1.Item, t1.Qty, t2.JobNo, t2.ItemCode AS ItemCode2, t2.Item AS Item2, t2.Qty AS Qty2, t2.MySeed
FROM #tmp1 AS t1 INNER JOIN (
SELECT *, ROW_NUMBER() OVER(PARTITION BY ItemCode ORDER BY JobNo) AS [MySeed]
FROM #tmp2
) AS t2 ON t1.ItemCode = t2.ItemCode
WHERE t2.MySeed = 1
UNION ALL
SELECT NULL AS ItemCode, NULL AS Item, NULL AS Qty, t2.JobNo, t2.ItemCode AS ItemCode2, t2.Item AS Item2, t2.Qty AS Qty2, t2.MySeed
FROM #tmp1 AS t1 INNER JOIN (
SELECT *, ROW_NUMBER() OVER(PARTITION BY ItemCode ORDER BY JobNo) AS [MySeed]
FROM #tmp2
) AS t2 ON t1.ItemCode = t2.ItemCode
WHERE t2.MySeed > 1
)
SELECT *
FROM MyCTE
ORDER BY ItemCode2, MySeed
I found a sample query online as above which is straight forward as it combines table 1 and table 2 and it assumes in table 2 if myseed count is 1 then input null values.
But, I need a query in snowflake for the scenario where table 1 can have any number of entries for each id and table 2 can also have multiple entries for each id. I need to join both the tables without duplicates and input null in the rows when the one table has multiple entries and other table don't have multiple entries.
How to write in snowflake(SNOWSQL)?
I need a result like below to combine two tables and avoid duplicates in either one of the table
so I want something as below in my query
select * from table a
where a.id in(select id, max(date) from table a group by id)
I am getting error here , as IN is equivalent to = .
how to do it?
example :
id
date
1
2022-31-01
1
2022-21-03
2
2022-01-01
2
2022-02-01
I need to get only one record based on date(max). The table has more columns than just id and date
so I need to something like this in snowflake
select * from table a
where id in(select id,max(date) from table a group by id)
```-----------------------
All solutions are working , if i select from table .
but i have case statement in view where duplicate records are coming
example :
create or replace view v_test
as
select * from
(
select id,lastdatetime,*,
case when start_date < timestamp and timestamp < end
and move_date = '9999-12-31' then 'Y'
else 'N' end as IND
from table a
) a
so if any one select view where IND= 'Y', more than 1 records are coming
what i want is to select latest records for ID where IND='Y' and max(lastdatetime)
how to incorporate this logic in view?
I think you are trying to get the latest record for each id?
select *
from table a
qualify row_number() over (partition by id order by date desc) = 1
So if we look at your sub-select:
using this "data" for the examples:
with data (id, _date) as (
select column1, to_date(column2, 'yyyy-dd-mm') from values
(1, '2022-31-01'),
(1, '2022-21-03'),
(2, '2022-01-01'),
(2, '2022-02-01')
)
select id, max(_date)
from data
group by 1;
it gives:
ID
MAX(_DATE)
1
2022-03-21
2
2022-01-02
which makes it seem you want the "the last date, per id"
which can classically (ansi sql) be written:
select d.*
from data as d
join (
select
id,
max(_date) as max_date
from data
group by 1
) as c
on d.id = c.id and d._date = c.max_date
;
ID
_DATE
1
2022-03-21
2
2022-01-02
which gives you "all the rows values". BUT if you have many rows with the same last date, you will get those, in the output.
Another methods is to use a ROW_NUMBER to pick one and only one row, which is the style of answer Mike has given:
with data (id, _date, extra) as (
select column1, to_date(column2, 'yyyy-dd-mm'), column3 from values
(1, '2022-31-01', 'extra_a'),
(1, '2022-21-03', 'extra_b_double_a'),
(1, '2022-21-03', 'extra_b_double_b'),
(2, '2022-01-01', 'extra_c'),
(2, '2022-02-01', 'extra_d')
)
select *
from data
qualify row_number() over (partition by id order by _date desc) =1 ;
gives:
ID
_DATE
EXTRA
1
2022-03-21
extra_b_double_a
2
2022-01-02
extra_d
now if you want the "all rows of the last day" you method works, albeit the QUALIFY/ROW_NUMBER is faster. You can use RANK
with data (id, _date, extra) as (
select column1, to_date(column2, 'yyyy-dd-mm'), column3 from values
(1, '2022-31-01', 'extra_a'),
(1, '2022-21-03', 'extra_b_double_a'),
(1, '2022-21-03', 'extra_b_double_b'),
(2, '2022-01-01', 'extra_c'),
(2, '2022-02-01', 'extra_d')
)
select *
from data
qualify dense_rank() over (partition by id order by _date desc) =1 ;
ID
_DATE
EXTRA
1
2022-03-21
extra_b_double_a
1
2022-03-21
extra_b_double_b
2
2022-01-02
extra_d
Now the last thing that it almost seems you are asking for, is "how do find the ID with the most recent data (here 1) and get all rows for that"
with data (id, _date, extra) as (
select column1, to_date(column2, 'yyyy-dd-mm'), column3 from values
(1, '2022-31-01', 'extra_a'),
(1, '2022-21-03', 'extra_b_double_a'),
(1, '2022-21-03', 'extra_b_double_b'),
(2, '2022-01-01', 'extra_c'),
(2, '2022-02-01', 'extra_d')
)
select *
from data
qualify id = last_value(id) over (order by _date);
Here is an example of how to use the in operator with a subquery:
select * from table1 t1 where t1.id in (select t2.id from table2 t2);
Usage of IN is possible to match on both columns:
select *
from tab AS a
where (a.id, a.date) in (select id, max(date) from tab group by id);
For sample data:
CREATE TABLE tab (id, date)
AS
SELECT column1, to_date(column2, 'yyyy-dd-mm')
FROM VALUES
(1, '2022-31-01'),
(1, '2022-21-03'),
(2, '2022-01-01'),
(2, '2022-02-01');
Output:
I am trying to get the statement on fetching the previous and next rows of a selected row.
Declare #OderDetail table
(
Id int primary key,
OrderId int,
ItemId int,
OrderDate DateTime2,
Lookup varchar(15)
)
INSERT INTO #OderDetail
VALUES
(1, 10, 1, '2018-06-11', 'A'),
(2, 10, 2, '2018-06-11', 'BE'), --this
(3, 2, 1, '2018-06-04', 'DR'),
(4, 2, 2, '2018-06-04', 'D'), --this
(5, 3, 2, '2018-06-14', 'DD'), --this
(6, 4, 2, '2018-06-14', 'R');
DECLARE
#ItemId int = 2,
#orderid int = 10
Required output:
Input for the procedure is order id =10 and item id =2 and i need to check item-2 is in the any other order i.e only previous and next item of matched record/order as per order date
Is this what your after? (Updated to reflect edit [OrderDate] to question)
Declare #OderDetail table
(
Id int primary key,
OrderId int,
ItemId int,
OrderDate DateTime2,
Lookup varchar(15)
)
INSERT INTO #OderDetail
VALUES
(1, 10, 1, '2018-06-11', 'A'),
(2, 10, 2, '2018-06-11', 'BE'), --this
(3, 2, 1, '2018-06-04', 'DR'),
(4, 2, 2, '2018-06-04', 'D'), --this
(5, 3, 2, '2018-06-14', 'DD'), --this
(6, 4, 2, '2018-06-14', 'R');
declare #ItemId int=2 , #orderid int = 10;
Query
With cte As
(
Select ROW_NUMBER() OVER(ORDER BY OrderDate) AS RecN,
*
From #OderDetail Where ItemId=#ItemId
)
Select Id, OrderId, ItemId, [Lookup] From cte Where
RecN Between ((Select Top 1 RecN From cte Where OrderId = #orderid) -1) And
((Select Top 1 RecN From cte Where OrderId = #orderid) +1)
Order by id
Result:
Id OrderId ItemId Lookup
2 10 2 BE
4 2 2 D
5 3 2 DD
Another possible approach is to use LAG() and LEAD() functions, that return data from a previous and subsequent row form the same resul tset.
-- Table
DECLARE #OrderDetail TABLE (
Id int primary key,
OrderId int,
ItemId int,
OrderDate DateTime2,
Lookup varchar(15)
)
INSERT INTO #OrderDetail
VALUES
(1, 10, 1, '2018-06-11', 'A'),
(2, 10, 2, '2018-06-11', 'BE'), --this
(3, 2, 1, '2018-06-04', 'DR'),
(4, 2, 2, '2018-06-04', 'D'), --this
(5, 3, 2, '2018-06-14', 'DD'), --this
(6, 4, 2, '2018-06-14', 'R');
-- Item and order
DECLARE
#ItemId int = 2,
#orderid int = 10
-- Statement
-- Get previois and next ID for every order, grouped by ItemId, ordered by OrderDate
;WITH cte AS (
SELECT
Id,
LAG(Id, 1) OVER (PARTITION BY ItemId ORDER BY OrderDate) previousId,
LEAD(Id, 1) OVER (PARTITION BY ItemId ORDER BY OrderDate) nextId,
ItemId,
OrderId,
Lookup
FROM #OrderDetail
)
-- Select current, previous and next order
SELECT od.*
FROM cte
CROSS APPLY (SELECT * FROM #OrderDetail WHERE Id = cte.Id) od
WHERE (cte.OrderId = #orderId) AND (cte.ItemId = #ItemId)
UNION ALL
SELECT od.*
FROM cte
CROSS APPLY (SELECT * FROM #OrderDetail WHERE Id = cte.previousId) od
WHERE (cte.OrderId = #orderId) AND (cte.ItemId = #ItemId)
UNION ALL
SELECT od.*
FROM cte
CROSS APPLY (SELECT * FROM #OrderDetail WHERE Id = cte.nextId) od
WHERE (cte.OrderId = #orderId) AND (cte.ItemId = #ItemId)
Output:
Id OrderId ItemId OrderDate Lookup
2 10 2 11/06/2018 00:00:00 BE
4 2 2 04/06/2018 00:00:00 D
5 3 2 14/06/2018 00:00:00 DD
Update to given this data set: I see where you are going with this. Note that in SOME cases there IS no row before the given one - so it only returns 2 not 3. Here I updated the CTE version. Un-comment the OTHER row to see 3 not 2 as there is then one before the selected row with that Itemid.
Added a variable to demonstrate how this is better allowing you to get 1 before and after or 2 before/after if you change that number (i.e. pass a parameter) - and if less rows, or none are before or after it gets as many as it can within that constraint.
Data setup for all versions:
Declare #OderDetail table
(
Id int primary key,
OrderId int,
ItemId int,
OrderDate DateTime2,
Lookup varchar(15)
)
INSERT INTO #OderDetail
VALUES
(1, 10, 1, '2018-06-11', 'A'),
(2, 10, 2, '2018-06-11', 'BE'), --this
(3, 2, 1, '2018-06-04', 'DR'),
(4, 2, 2, '2018-06-04', 'D'), --this
(5, 3, 2, '2018-06-14', 'DD'), --this
(9, 4, 2, '2018-06-14', 'DD'),
(6, 4, 2, '2018-06-14', 'R'),
--(10, 10, 2, '2018-06-02', 'BE'), -- un-comment to see one before
(23, 4, 2, '2018-06-14', 'R');
DECLARE
#ItemId int = 2,
#orderid int = 2;
CTE updated version:
DECLARE #rowsBeforeAndAfter INT = 1;
;WITH cte AS (
SELECT
Id,
OrderId,
ItemId,
OrderDate,
[Lookup],
ROW_NUMBER() OVER (ORDER BY OrderDate,Id) AS RowNumber
FROM #OderDetail
WHERE
ItemId = #itemId -- all matches of this
),
myrow AS (
SELECT TOP 1
Id,
OrderId,
ItemId,
OrderDate,
[Lookup],
RowNumber
FROM cte
WHERE
ItemId = #itemId
AND OrderId = #orderid
)
SELECT
cte.Id,
cte.OrderId,
cte.ItemId,
cte.OrderDate,
cte.[Lookup],
cte.RowNumber
FROM ctE
INNER JOIN myrow
ON ABS(cte.RowNumber - myrow.RowNumber) <= #rowsBeforeAndAfter
ORDER BY OrderDate, OrderId;
You probably want the CTE method (See an original at the end of this) however:
Just to point out, this gets the proper results but is probably not what you are striving for since it is dependent on the row order and the item id not the actual row with those two values:
SELECT TOP 3
a.Id,
a.OrderId,
a.ItemId,
a.Lookup
FROM #OderDetail AS a
WHERE
a.ItemId = #ItemId
To fix that, you can use an ORDER BY and TOP 1 with a UNION, kind of ugly. (UPDATED with date sort and != on the id.)
SELECT
u.Id,
u.OrderId,
u.OrderDate,
u.ItemId,
u.Lookup
FROM (
SELECT
a.Id,
a.OrderId,
a.OrderDate,
a.ItemId,
a.Lookup
FROM #OderDetail AS a
WHERE
a.ItemId = #ItemId
AND a.OrderId = #orderid
UNION
SELECT top 1
b.Id,
b.OrderId,
b.OrderDate,
b.ItemId,
b.Lookup
FROM #OderDetail AS b
WHERE
b.ItemId = #ItemId
AND b.OrderId != #orderid
ORDER BY b.OrderDate desc, b.OrderId
UNION
SELECT top 1
b.Id,
b.OrderId,
b.OrderDate,
b.ItemId,
b.Lookup
FROM #OderDetail AS b
WHERE
b.ItemId = #ItemId
AND b.OrderId != #orderid
ORDER BY b.OrderDate asc, b.OrderId
) AS u
ORDER BY u.OrderDate asc, u.OrderId
I think its simple, you can check with min(Id) and Max(id) with left outer join or outer apply
like
Declare #ItemID int = 2
Select * From #OderDetail A
Outer Apply (
Select MIN(A2.Id) minID, MAX(A2.Id) maxID From #OderDetail A2
Where A2.ItemId =#ItemID
) I05
Outer Apply(
Select * From #OderDetail Where Id=minID-1
Union All
Select * From #OderDetail Where Id=maxID+1
) I052
Where A.ItemId =#ItemID Order By A.Id
Let me know if this helps you or you face any problem with it...
Regards,
So, apparently, I have everything right according to my professor except for one column that shows the rank of the columns shown in the code below. I'm thinking that, essentially, it just has to show the row numbers off to the left side in its own column. Here are the instructions:
The sales manager would now like you to create a report that ranks her
products by both their total sales and total sales quantity (each will
be its own column). Create a stored procedure that returns the
following columns but also with the two new rank columns added.
Product Name | Orders Count | Total Sales Value | Total Sales
Quantity
I know that it doesn't have that extra column in the assignment description, but I guess I need it. Here is what I have so far:
USE OnlineStore
GO
CREATE PROC spManagerProductSalesCount
AS
BEGIN
SELECT
P.Name AS 'Product Name',
Isnull(Count(DISTINCT O.OrderID), 0) AS 'Orders Count',
Sum(Isnull(O.OrderTotal, 0)) AS 'Total Sales Value',
Sum (Isnull(OI.OrderItemQuantity, 0)) AS 'Total Sales Quantity'
FROM
Product P
INNER JOIN
OrderItem OI ON P.ProductID = OI.ProductID
INNER JOIN
Orders O on O.OrderID = OI.OrderID
GROUP BY
P.Name
ORDER BY
'Total Sales Value' DESC, 'Total Sales Quantity' DESC
END
Update: It does need to be in a stored procedure and CTEs can/should be used. I could use some help with the CTEs. Those are pretty difficult for me.
This is just the select part of the stored proc but it should show you what to do:
declare #products table
(
Name varchar(50),
id int
)
declare #orderitems table
(
id int,
orderid int,
productid int,
orderitemquantity int
)
declare #orders table
(
orderid int,
ordertotal decimal(18,2)
)
insert into #products VALUES ('apple', 1)
insert into #products VALUES ('orange', 2)
insert into #products VALUES ('pear', 3)
insert into #products VALUES ('melon', 4)
insert into #orders values(1, 19.0)
insert into #orders values(2, 25.5)
insert into #orders values(3, 9.5)
insert into #orders values(4, 13.5)
insert into #orders values(5, 8.5)
insert into #orderitems VALUES(1, 1, 1, 20)
insert into #orderitems VALUES(2, 1, 2, 10)
insert into #orderitems VALUES(3, 2, 3, 5)
insert into #orderitems VALUES(4, 2, 4, 4)
insert into #orderitems VALUES(5, 3, 1, 10)
insert into #orderitems VALUES(6, 3, 2, 5)
insert into #orderitems VALUES(7, 4, 3, 3)
insert into #orderitems VALUES(8, 4, 4, 2)
insert into #orderitems VALUES(9, 5, 1, 5)
insert into #orderitems VALUES(10, 5, 4, 2)
;WITH summary as
(
SELECT p.Name as ProductName,
COUNT(o.orderid) as 'Orders Count',
ISNULL(Sum(o.ordertotal),0) AS 'Total Sales Value',
ISNULL(Sum(oi.orderitemquantity),0) AS 'Total Sales Quantity'
FROM #products p
INNER JOIN #orderitems oi on oi.productid = p.id
INNER JOIN #orders o on o.orderid = oi.orderid
GROUP BY p.Name
)
SELECT ProductName, [Orders Count], [Total Sales Value], [Total Sales Quantity],
RANK() OVER (ORDER BY [Total Sales Value] DESC) AS ValueRanking,
RANK() OVER (ORDER BY [Total Sales Quantity] DESC) AS QuantityRanking FROM summary
Notice a few things here. This code can be cut and pasted into a Management Studio query window and run as such. It starts with some table declarations and insert of sample data. When asking a question it is always useful if you do this part of the work; people are much more likely to answer, if the most boring bit is done!
COUNT() does not need ISNULL protection; it returns 0, if there are no values.
Given the final data, you will see that the ValueRanking and QuantityRankings are different (I fiddled the data to get this, just to illustrate the point). What this means is that the final result can only be ordered by one of them (or indeed by any other column - order by is not dependent on ranking).
HTH
I have a table containing orders. I would like to select those orders that are a certain number of days apart for a specific client. For example, in the table below I would like to select all of the orders for CustomerID = 10 that are at least 30 days apart from the previous instance. With the starting point to be the first occurrence (07/05/2014 in this data).
OrderID | CustomerID | OrderDate
==========================================
1 10 07/05/2014
2 10 07/15/2014
3 11 07/20/2014
4 11 08/20/2014
5 11 09/21/2014
6 10 09/23/2014
7 10 10/15/2014
8 10 10/30/2014
I would want to select OrderIDs (1,6,8) since they are 30 days apart from each other and all from CustomerID = 10. OrderIDs 2 and 7 would not be included as they are within 30 days of the previous order for that customer.
What confuses me is how to set the "checkpoint" to the last valid date. Here is a little "pseudo" SQL.
SELECT OrderID
FROM Orders
WHERE CusomerID = 10
AND OrderDate > LastValidOrderDate + 30
i came here and i saw #SveinFidjestøl already posted answer but i can't control my self after by long tried :
with the help of LAG and LEAD we can comparison between same column
and as per your Q you are looking 1,6,8. might be this is helpful
SQL SERVER 2012 and after
declare #temp table
(orderid int,
customerid int,
orderDate date
);
insert into #temp values (1, 10, '07/05/2014')
insert into #temp values (2, 10, '07/15/2014')
insert into #temp values (3, 11, '07/20/2014')
insert into #temp values (4, 11, '08/20/2014')
insert into #temp values (5, 11, '09/21/2014')
insert into #temp values (6, 10, '09/23/2014')
insert into #temp values (7, 10, '10/15/2014')
insert into #temp values (8, 10, '10/30/2014');
with cte as
(SELECT orderid,customerid,orderDate,
LAG(orderDate) OVER (ORDER BY orderid ) PreviousValue,
LEAD(orderDate) OVER (ORDER BY orderid) NextValue,
rownum = ROW_NUMBER() OVER (ORDER BY orderid)
FROM #temp
WHERE customerid = 10)
select orderid,customerid,orderDate from cte
where DATEDIFF ( day , PreviousValue , orderDate) > 30
or PreviousValue is null or NextValue is null
SQL SERVER 2005 and after
WITH CTE AS (
SELECT
rownum = ROW_NUMBER() OVER (ORDER BY p.orderid),
p.orderid,
p.customerid,
p.orderDate
FROM #temp p
where p.customerid = 10)
SELECT CTE.orderid,CTE.customerid,CTE.orderDate,
prev.orderDate PreviousValue,
nex.orderDate NextValue
FROM CTE
LEFT JOIN CTE prev ON prev.rownum = CTE.rownum - 1
LEFT JOIN CTE nex ON nex.rownum = CTE.rownum + 1
where CTE.customerid = 10
and
DATEDIFF ( day , prev.orderDate , CTE.orderDate) > 30
or prev.orderDate is null or nex.orderDate is null
GO
You can use the LAG() function, available in SQL Server 2012, together with a Common Table Expression. You calculate the days between the customer's current order and the customer's previous order and then query the Common Table Expression using the filter >= 30
with cte as
(select OrderId
,CustomerId
,datediff(d
,lag(orderdate) over (partition by CustomerId order by OrderDate)
,OrderDate) DaysSinceLastOrder
from Orders)
select OrderId, CustomerId, DaysSinceLastOrder
from cte
where DaysSinceLastOrder >= 30 or DaysSinceLastOrder is null
Results:
OrderId CustomerId DaysSinceLastOrder
1 10 NULL
6 10 70
3 11 NULL
4 11 31
5 11 32
(Note that 1970-01-01 is chosen arbitrarily, you may choose any date)
Update
A slighty more reliable way of doing it will involve a temporary table. But the original table tbl can be left unchanged. See here:
CREATE TABLE #tmp (id int); -- set-up temp table
INSERT INTO #tmp VALUES (1); -- plant "seed": first oid
WHILE (##ROWCOUNT>0)
INSERT INTO #tmp (id)
SELECT TOP 1 OrderId FROM tbl
WHERE OrderId>0 AND CustomerId=10
AND OrderDate>(SELECT max(OrderDate)+30 FROM tbl INNER JOIN #tmp ON id=OrderId)
ORDER BY OrderDate;
-- now list all found entries of tbl:
SELECT * FROM tbl WHERE EXISTS (SELECT 1 FROM #tmp WHERE id=OrderId)
#tinka shows how to use CTEs to do the trick, and the new windowed functions (for 2012 and later) are probably the best answer. There is also the option, assuming you do not have a very large data set, to use a recursive CTE.
Example:
declare #customerid int = 10;
declare #temp table
(orderid int,
customerid int,
orderDate date
);
insert into #temp values (1, 10, '07/05/2014')
insert into #temp values (2, 10, '07/15/2014')
insert into #temp values (3, 11, '07/20/2014')
insert into #temp values (4, 11, '08/20/2014')
insert into #temp values (5, 11, '09/21/2014')
insert into #temp values (6, 10, '09/23/2014')
insert into #temp values (7, 10, '10/15/2014')
insert into #temp values (8, 10, '10/30/2014');
with datefilter AS
(
SELECT row_number() OVER(PARTITION BY CustomerId ORDER BY OrderDate) as RowId,
OrderId,
CustomerId,
OrderDate,
DATEADD(day, 30, OrderDate) as FilterDate
from #temp
WHERE CustomerId = #customerid
)
, firstdate as
(
SELECT RowId, OrderId, CustomerId, OrderDate, FilterDate
FROM datefilter
WHERE rowId = 1
union all
SELECT datefilter.RowId, datefilter.OrderId, datefilter.CustomerId,
datefilter.OrderDate, datefilter.FilterDate
FROM datefilter
join firstdate
on datefilter.CustomerId = firstdate.CustomerId
and datefilter.OrderDate > firstdate.FilterDate
WHERE NOT EXISTS
(
SELECT 1 FROM datefilter betweens
WHERE betweens.CustomerId = firstdate.CustomerId
AND betweens.orderdate > firstdate.FilterDate
AND datefilter.orderdate > betweens.orderdate
)
)
SELECT * FROM firstdate