I'm trying to understand how case when exists expression works, there is two tables one is trOrderHeader which stores main info about any order. Other is trOrderLine which stores details about an order and there is a column IsClosed which indicates Order is somehow closed (canceled or completed).
So my query is below which I am trying to get OrderLineID with IsClosed column (I can do it by joins it is easy but I am trying case when exists expression) but all IsClosed column returns 1;
SELECT
OrderLineId,
IsClosed =
CASE
WHEN EXISTS (select * from trOrderHeader where IsClosed=1)
THEN 1
WHEN EXISTS (select * from trOrderHeader where IsClosed=0)
THEN 0
END
FROM
trOrderLine
GROUP BY OrderLineId
Isn't this supposed to give me if an Order is Closed write 1, if an Order is not Closed write 0?
Did I misunderstand case when exists expression?
You would need to correlate the subqueries. Assuming that column OrderId can be used to relate the tables, then:
SELECT
OrderLineId,
IsClosed =
CASE
WHEN EXISTS (select 1 from trOrderHeader h where h.IsClosed = 1 AND h.OrderId = l.OrderId)
THEN 1
WHEN EXISTS (select 1 from trOrderHeader h where IsClosed = 0 AND h.OrderId = l.OrderId)
THEN 0
END
FROM trOrderLine l
GROUP BY OrderLineId
However, the logic of the query could probably be simplified by using a JOIN and an aggregate function to compute the status. Something like this could be what you need:
SELECT l.OrderLineId, MAX(h.isClosed) IsClosed
FROM trOrderLine l
INNER JOIN trOrderHeader h ON h.OrderId = l.OrderId
GROUP BY l.OrderLineId
Related
I am working on Postgres and I have two tables vehicles and vehicles_flag. There are no relations between the two tables and hence we can not join two tables to fetch the required data.
The table structure is below (vehicle_flag table may not contain all the id present in the vehicle table) :
[Table structure]
I am writing a function that will accept multiple input parameters. I have to select vehicle id from the vehicle_flag table only if the flag value is true: otherwise, I have to ignore the vehicel_flag table. My aim is to achieve something like this, but turns out the case statement expects scaler output:
select count(id) from vehicles
where
vehicles.id in (case
when #hasbluetooth =1 then (select distinct id from vehicle_flags where flag='bluetooth' and value = '1')
else
(select distinct id from vehicles)
end)
and
vehicles.id in (case
when #hasac =1 then (select distinct id from vehicle_flags where flag='ac' and value = '1')
else
(select distinct id from vehicles)
end)
Kindly suggest any solution to achieve this.
I suspect you want:
select v.*
from vehicle v
left join vehicle_flags vf on vf.id = v.id
group by v.id
having
(#hasbluetooth = 0 or bool_or(vf.flag = 'bluetooth' and vf.value = 1)
and (#hasac = 0 or bool_or(vf.flag = 'ac' and vf.value = 1)
I trying to create a SQL query with a CASE WHEN EXISTS clause in SQL Server. I assume I am doing something wrong as when I run the SELECT * FROM [Christmas_Sale] it takes forever for SQL to load the code.
CREATE VIEW [Christmas_Sale]
AS
SELECT
C.*,
CASE
WHEN EXISTS (SELECT S.Sale_Date
FROM [Christmas_Sale] s
WHERE C.ID = S.ID)
THEN 0
ELSE 1
END AS ChristmasSale
FROM
[Customer_Detail] C ;
I'm trying to write a sub select which I need to return a 1 if Sale_Date= 1 and 0 for anything else.
The syntax of your query looks ok. But since your stated:
I'm trying to write a sub select which I need to return a 1 if Sale_Date= 1 and 0 for anything else.
... Then you could rephrase your query by adding one more condition in the WHERE clause of the subquery:
CREATE VIEW [Christmas_Sale]AS
SELECT
C.*,
CASE WHEN EXISTS (
SELECT 1
FROM [Christmas_Sale] s
WHERE C.ID = S.ID and S.Sale_Date = 1
) THEN 0 ELSE 1 END AS ChristmasSale
FROM [Customer_Detail] C ;
If a record exists in [Christmas_Sale] with the corresponding ID and Sale_Date = 1, then ChristmasSale will have value 1, else it will display 0.
This query looks correct:
CREATE VIEW [Christmas_Sale] AS
SELECT C.*,
(CASE WHEN EXISTS (SELECT 1
FROM [Christmas_Sale] s
WHERE C.ID = S.ID
)
THEN 0 ELSE 1
END) AS ChristmasSale
FROM [Customer_Detail] C ;
If performance is an issue, you want an index on Christmas_Sale(ID).
Note that the SELECT S.Sale_Date in the subquery is meaningless, because EXISTS checks for rows not columns. Hence, I replaced it with the simpler 1.
I have written a SQL query with a subquery to include counts. When the count is 0, and I try to filter out the 0, it turns the 0's to NULLs and keeps the rows, and vice versa. The result is that I can't filter out the 0's, which was the purpose of including the counts.
SELECT distinct
a
,b
,
(SELECT
count(id)
FROM seq_stud
WHERE scs.SequenceID = seq_stud.SequenceID
and seq_stud.EndDate is null
HAVING count(id) <> 0
) As t1
FROM sp
INNER JOIN p on sp.ProgramID = p.ProgramID
...etc.
Does anyone know why this is happening and how I can filter out the 0 counts?
You don't filter in the SELECT clause. If you don't want rows that have no match in seq_stud, then use WHERE:
WHERE EXISTS (SELECT 1
FROM seq_stud ss
WHERE scs.SequenceID = ss.SequenceID and ss.EndDate is null
)
I would remove the HAVING statement altogether. You need to put that in the WHERE clause. Otherwise, it will return null, as you found.
SELECT distinct a, b,
(SELECT count(id)
FROM seq_stud
WHERE scs.SequenceID = seq_stud.SequenceID
and seq_stud.EndDate is null
) As t1
FROM sp
INNER JOIN p on sp.ProgramID = p.ProgramID
WHERE t1 > 0
I just figured this out. The Select subquery should be included as a WHERE statement
Using having count() in exists clause
I'm trying to create a query so that I can have a column show Y/N if a particular item was ordered for a group of orders. The item I'm looking for would be OLI.id = '538'.
So my results would be:
Order#, Customer#, FreightPaid
12345, 00112233, Y
12346, 00112233, N
I cannot figure out if I need to use a subquery or the where exists function ?
Here's my current query:
SELECT distinct
OrderID,
Accountuid as Customerno
FROM [SMILEWEB_live].[dbo].[OrderLog] OL
inner join Orderlog_item OLI on OLI.orderlogkey = OL.[key]
inner join Account A on A.uid = OL.Accountuid
where A.GroupId = 'X9955'
and OL.CreateDate >= GETDATE() - 60
I would suggest an exists clause instead of a join:
select ol.OrderID, ol.Accountuid as Customerno,
(case when exists (select 1
from Orderlog_item OLI join
Account A
on A.uid = OL.Accountuid
where OLI.orderlogkey = OL.[key] and A.GroupId = 'X9955'
)
then 1 else 0
end) as flag
from [SMILEWEB_live].[dbo].[OrderLog] OL
where OL.CreateDate >= GETDATE() - 60;
This prevents a couple of problems. First, duplicate rows which are caused when there are multiple matching rows (and select distinct add unnecessary overhead). Second, missing rows, which happen when you use inner join instead of an outer join.
I am trying to increment a column on a sql server table based on the join between the initial table and the joined table. The idea is to update tblForm10Objectives, set the ObjectiveNumber column to an increment number starting with 1 based on the number of rows returned from the join of tblForm10GoalsObjectives and tblForm10Objectives where ID_Form10Goal equals a number. Example query so far:
Update tblForm10Objectives
Set ObjectiveNumber = rn
From (
Select ROW_NUMBER() over (PARTITION by OG.ID_Form10Goal) as rn
, *
From (
Select *
From tblForm10GoalsObjectives OG
Join tblForm10Objectives O On OG.ID_Form10Objective = O.ID_Form10Objective
Where OG.ID_Form10Goal = 4
Order by O.ID_Form10Objective
) as tblForm10Objectives;
If the select portion of the query is performed the columns are displayed so you can see the ObjectiveNumber is currently 0 where ID_Form10Goal = 4
Once the update runs I need for the ObjectiveNumber to show 1 , 2; since there are two rows for ID_Form10Goal = 4.
I had to introduce a new table to the logic of this update statement, the table name is tblForm10Goals. The objectives need to be pulled by ID_Agency instead of ID_Form10Goal I am getting an error message stating a "a multipart identifier 'dbo.tblForm10Objectives.ID_Form10Objective = rns.ID_Form10Objective' could not be bound. I am using the following SQL Update statement:
UPDATE dbo.tblForm10Objectives
SET ObjectiveNumber = rn
FROM tblForm10Goals As g
Left Join tblForm10GoalsObjectives gobs ON g.ID_Form10Goal = gobs.ID_Form10Goal
Right Join
(
SELECT
ROW_NUMBER() OVER (PARTITION BY g.ID_Agency
ORDER BY OB.ID_Form10Objective) AS rn,
OB.ID_Form10Objective
FROM tblForm10Goals g
LEFT JOIN dbo.tblForm10GoalsObjectives gobs ON g.ID_Form10Goal = gobs.ID_Form10Goal
RIGHT JOIN dbo.tblForm10Objectives OB ON gobs.ID_Form10Objective = OB.ID_Form10Objective
Where g.ID_Agency = 2
) rns ON dbo.tblForm10Objectives.ID_Form10Object = rns.ID_Form10Objective
Your example seems to be missing a closing parenthesis somewhere, and without the table structures to look at, I can't be certain of my answer. It seems you have two tables:
tblForm10Objectives
-------------------
ID_Form10Objective
ObjectiveNumber
...
and
tblForm10GoalsObjectives
------------------------
ID_Form10Goal
ID_Form10Objective
...
If this is the case, the following query should give you the results you desire:
UPDATE dbo.tblForm10Objectives
SET ObjectiveNumber = rn
FROM dbo.tblForm10Objectives INNER JOIN
(
SELECT
ROW_NUMBER() OVER (PARTITION BY OG.ID_Form10Goal
ORDER BY O.ID_Form10Objective) AS rn,
O.ID_Form10Objective
FROM dbo.tblForm10Objectives O INNER JOIN
dbo.tblForm10GoalsObjectives OG ON OG.ID_Form10Objective = O.ID_Form10Objective
Where OG.ID_Form10Goal = 4
) rns ON dbo.tblForm10Objectives.ID_Form10Objective = rns.ID_Form10Objective
If you run the inner SELECT statement, you will see the desired ObjectiveNumber values and the corresponding ID_Form10Objective that will get updated with those values.
If you post your table structures, I or someone else may be able to be of more help.