I have two date columns.
Sometimes they both have dates(Which will be same always in both the columns) and sometimes one is empty and one has date value.
So, instead of two columns, I am trying to get one column.
If one is empty it will take date value from other column and if both have values(which will always be same) it will just take any of the value from the two columns.
I have tried UNION commands but its not giving me the desired result.
SQL Server has a couple different options for this scenario. You can use COALESCE, ISNULL, or a CASE statement.
Based on the information you provided I would use COALESCE. It offers several benefits over ISNULL and is very simple to implement. A CASE statement seems like overkill for what you are trying to do. Check out the link above for more info on each solution.
Welcome to Stack Overflow!
You need Coalesce
Also, in the future, you should put sample data and metadata in text in your question, rather than as attachments.
You could use the ISNULL statement if it is SQL
SELECT ISNULL(ReturnDate,RepartureDate) as dateAct FROM AviationReservation_dev
UPDATE tableName
SET Date1Column = ISNULL(Date1Column, Date2Column);
Context: ISNULL ( check_expression , replacement_value ), if first argument is not null, it will use that argument.
After the update, delete the other column.
It seems there is no case for both column to be empty, then in such condition, you can do something like this:
SELECT
CASE
WHEN column1 IS NULL THEN column2
WHEN column2 IS NULL THEN column1
ELSE column1 orcolumn2
Related
I have a table that I need to add the same values to a whole bunch of items
(in a nut shell if the item doesn't have a UNIT of "CTN" I want to add the same values i have listed to them all)
I thought the following would work but it doesn't :(
Any idea what i am doing wrong ?
INSERT INTO ICUNIT
(UNIT,AUDTDATE,AUDTTIME,AUDTUSER,AUDTORG,CONVERSION)
VALUES ('CTN','20220509','22513927','ADMIN','AU','1')
WHERE ITEMNO In '0','etc','etc','etc'
If I understand correctly you might want to use INSERT INTO ... SELECT from original table with your condition.
INSERT INTO ICUNIT (UNIT,AUDTDATE,AUDTTIME,AUDTUSER,AUDTORG,CONVERSION)
SELECT 'CTN','20220509','22513927','ADMIN','AU','1'
FROM ICUNIT
WHERE ITEMNO In ('0','etc','etc','etc')
The query you needs starts by selecting the filtered items. So it seems something like below is your starting point
select <?> from dbo.ICUNIT as icu where icu.UNIT <> 'CTN' order by ...;
Notice the use of schema name, terminators, and table aliases - all best practices. I will guess that a given "item" can have multiple rows in this table so long as ICUNIT is unique within ITEMNO. Correct? If so, the above query won't work. So let's try slightly more complicated filtering.
select distinct icu.ITEMNO
from dbo.ICUNIT as icu
where not exists (select * from dbo.ICUNIT as ctns
where ctns.ITEMNO = icu.ITEMNO -- correlating the subquery
and ctns.UNIT = 'CTN')
order by ...;
There are other ways to do that above but that is one common way. That query will produce a resultset of all ITEMNO values in your table that do not already have a row where UNIT is "CTN". If you need to filter that for specific ITEMNO values you simply adjust the WHERE clause. If that works correctly, you can use that with your insert statement to then insert the desired rows.
insert into dbo.ICUNIT (...)
select distinct icu.ITEMNO, 'CTN', '20220509', '22513927', 'ADMIN', 'AU', '1'
from ...
;
I am trying to do a select on a table with around 35.000 rows, one of the columns is a varbinary with may have some NULL values and I need to exclude those NULL values from my results.
The problem is: when you do a select on a varbinary column, it takes a lot of time to complete, I've found a way that I'm not sure I can use or is the best way to do something like that and I would like some opinions.
Here is it:
SELECT REQUEST,REQLOCATION,DESCRIPT,BLOBNAME,BLOBSIZE,substring(BLOBVALUE,0,1) AS BLOBVALUE,BLOBMODE,BLOBPATH,BLOBID,
REDIRID,ANALYST,CLIENT,SEVENT,PACKAGE,INSERTDATE
FROM REQBLOB WHERE substring(BLOBVALUE,0,1) IS NOT NULL
The varbinary column is the "BLOBVALUE" one where I do a "substring" select and this query gave me a result of 20.000 rows instantly and I think it's returned only valid data, not NULLs, what you think about that?
Get rid of the SUBSTRING in the WHERE, it's making your query non-SARGable; that's why it's slow.
SELECT REQUEST,
REQLOCATION,
DESCRIPT,
BLOBNAME,
BLOBSIZE,
SUBSTRING(BLOBVALUE, 0, 1) AS BLOBVALUE,
BLOBMODE,
BLOBPATH,
BLOBID,
REDIRID,
ANALYST,
CLIENT,
SEVENT,
PACKAGE,
INSERTDATE
FROM REQBLOB
WHERE BLOBVALUE IS NOT NULL;
Why are you using substring on a varbinary anyway though..?
I am working on an SSRS report and a part of my sql query is like
WHERE SuperVisorId IN (#SupervisorIDs) AND CreatedDate> #StartDate
where the #SupervisorIDs is a dropdown with option of "select all" and individual supervisors.
So if the supervisors "all" option is selected , then I don't need to include that in the where clause and my where clause is only this
WHERE CreatedDate> #StartDate
So how can I make the WHERE clause looks different according to Selection of dropdown?
This only applies if you are using a single valued parameter with a manually added All option to the list of available values. Multi-value parameters do not know when all options are selected.
SQL Server doesn't always execute the conditions in a where clause in the order you write them, so if you are using where (#p = 'all' or col = #p) and ... you may still be comparing your values.
If performance is a concern, you can avoid this by using a short circuiting case, that only progresses to the actual data comparison if it is necessary:
where case when #SupervisorIDs = 'All' then 1
else case when SuperVisorId = #SupervisorIDs then 1
else 0
end
end = 1
and CreatedDate > #StartDate
Assuming that you are using a dataset query to populate the supervisor parameter dropdown, then you can try this.
Create an additional hidden parameter of a boolean type. For this example, I'll call it #AllSupsSelected. Set the default value of the parameter to:
=COUNT(Parameters!SupervisorIds.Label)=COUNT(Fields!SupervisorIdLabel.Value,"SupervisorDataset")
Replace the field and dataset names accordingly. If the dataset is returning non-distinct values, you may have to tinker further to get this working.
Now your query can read:
WHERE #AllSupsSelected OR SupervisorId IN (#SupervisorIds)
Make your where clause like below
WHERE (
(SuperVisorId IN (#SupervisorIDs))
OR (
#SupervisorIDs = 0
AND COLUMN_WITH_NULL IS NOT NULL
)
)
AND CreatedDate > #StartDate
And pass 0 when selected "select all"
As an actual answer to your particular problem, set your multi-valued parameter dataset up similar to this to return all Supervisors as well as a value at the bottom of the list for No Supervisor:
select distinct SupervisorID as Value
,SupervisorName as Label
,1 as Sort
from Suppliers
union all
select <Uniquely identifiable value with the same data type as SupervisorID> as Value
,'No Supervisor' as Label
,2 as Sort
order by Sort
,Label
Then in your dataset set up your filtering similar to the below. I have structured it in this manner to avoid using the isnull function on your SupervisorID column, which will hurt the query performance:
select cols
from tables
where SupervisorID in(#SupervisorID)
or (SupervisorID is null
and <Unique value from above> in (#SupervisorID)
)
which version of ssrs ? in 2016, you don't need to alter your query. when you click "select all" by default it pass all the values. so your query works good without changing anything.
thanks,
SK
I am trying to order by date. I want the most recent dates coming in first. That's easy enough, but there are many records that are null and those come before any records that have a date.
I have tried a few things with no success:
ORDER BY ISNULL(Next_Contact_Date, 0)
ORDER BY ISNULL(Next_Contact_Date, 999999999)
ORDER BY coalesce(Next_Contact_Date, 99/99/9999)
How can I order by date and have the nulls come in last? The data type is smalldatetime.
smalldatetime has range up to June 6, 2079 so you can use
ORDER BY ISNULL(Next_Contact_Date, '2079-06-05T23:59:00')
If no legitimate records will have that date.
If this is not an assumption you fancy relying on a more robust option is sorting on two columns.
ORDER BY CASE WHEN Next_Contact_Date IS NULL THEN 1 ELSE 0 END, Next_Contact_Date
Both of the above suggestions are not able to use an index to avoid a sort however and give similar looking plans.
One other possibility if such an index exists is
SELECT 1 AS Grp, Next_Contact_Date
FROM T
WHERE Next_Contact_Date IS NOT NULL
UNION ALL
SELECT 2 AS Grp, Next_Contact_Date
FROM T
WHERE Next_Contact_Date IS NULL
ORDER BY Grp, Next_Contact_Date
According to Itzik Ben-Gan, author of T-SQL Fundamentals for MS SQL Server 2012, "By default, SQL Server sorts NULL marks before non-NULL values. To get NULL marks to sort last, you can use a CASE expression that returns 1 when the" Next_Contact_Date column is NULL, "and 0 when it is not NULL. Non-NULL marks get 0 back from the expression; therefore, they sort before NULL marks (which get 1). This CASE expression is used as the first sort column." The Next_Contact_Date column "should be specified as the second sort column. This way, non-NULL marks sort correctly among themselves." Here is the solution query for your example for MS SQL Server 2012 (and SQL Server 2014):
ORDER BY
CASE
WHEN Next_Contact_Date IS NULL THEN 1
ELSE 0
END, Next_Contact_Date;
Equivalent code using IIF syntax:
ORDER BY
IIF(Next_Contact_Date IS NULL, 1, 0),
Next_Contact_Date;
order by -cast([Next_Contact_Date] as bigint) desc
If your SQL doesn't support NULLS FIRST or NULLS LAST, the simplest way to do this is to use the value IS NULL expression:
ORDER BY Next_Contact_Date IS NULL, Next_Contact_Date
to put the nulls at the end (NULLS LAST) or
ORDER BY Next_Contact_Date IS NOT NULL, Next_Contact_Date
to put the nulls at the front. This doesn't require knowing the type of the column and is easier to read than the CASE expression.
EDIT: Alas, while this works in other SQL implementations like PostgreSQL and MySQL, it doesn't work in MS SQL Server. I didn't have a SQL Server to test against and relied on Microsoft's documentation and testing with other SQL implementations. According to Microsoft, value IS NULL is an expression that should be usable just like any other expression. And ORDER BY is supposed to take expressions just like any other statement that takes an expression. But it doesn't actually work.
The best solution for SQL Server therefore appears to be the CASE expression.
A bit late, but maybe someone finds it useful.
For me, ISNULL was out of question due to the table scan. UNION ALL would need me to repeat a complex query, and due to me selecting only the TOP X it would not have been very efficient.
If you are able to change the table design, you can:
Add another field, just for sorting, such as Next_Contact_Date_Sort.
Create a trigger that fills that field with a large (or small) value, depending on what you need:
CREATE TRIGGER FILL_SORTABLE_DATE ON YOUR_TABLE AFTER INSERT,UPDATE AS
BEGIN
SET NOCOUNT ON;
IF (update(Next_Contact_Date)) BEGIN
UPDATE YOUR_TABLE SET Next_Contact_Date_Sort=IIF(YOUR_TABLE.Next_Contact_Date IS NULL, 99/99/9999, YOUR_TABLE.Next_Contact_Date_Sort) FROM inserted i WHERE YOUR_TABLE.key1=i.key1 AND YOUR_TABLE.key2=i.key2
END
END
Use desc and multiply by -1 if necessary. Example for ascending int ordering with nulls last:
select *
from
(select null v union all select 1 v union all select 2 v) t
order by -t.v desc
I know this is old but this is what worked for me
Order by Isnull(Date,'12/31/9999')
I think I found a way to show nulls in the end and still be able to use indexes for sorting.
The idea is super simple - create a calculatable column which will be based on existing column, and put an index on it.
ALTER TABLE dbo.Users
ADD [FirstNameNullLast]
AS (case when [FirstName] IS NOT NULL AND (ltrim(rtrim([FirstName]))<>N'' OR [FirstName] IS NULL) then [FirstName] else N'ZZZZZZZZZZ' end) PERSISTED
So, we are creating a persisted calculatable column in the SQL, in that column all blank and null values will be replaced by 'ZZZZZZZZ', this will mean, that if we will try to sort based on that column, we will see all the null or blank values in the end.
Now we can use it in our new index.
Like this:
CREATE NONCLUSTERED INDEX [IX_Users_FirstNameNullLast] ON [dbo].[Users]
(
[FirstNameNullLast] ASC
)
So, this is an ordinary nonclustered index. We can change it however we want, i.e. include extra columns, increase number of indexes columns, change sorting order etc.
I know this is a old thread, but in SQL Server nulls are always lower than non-null values. So it's only necessary to order by Desc
In your case Order by Next_Contact_Date Desc should be enough.
Source: order by with nulls- LearnSql
I have a select statement with calculated columns and I would like to use the value of one calculated column in another. Is this possible? Here is a contrived example to show what I am trying to do.
SELECT [calcval1] = CASE Statement, [calcval2] = [calcval1] * .25
No.
All the results of a single row from a select are atomic. That is, you can view them all as if they occur in parallel and cannot depend on each other.
If you're referring to computed columns, then you need to update the formula's input for the result to change during a select.
Think of computed columns as macros or mini-views which inject a little calculation whenever you call them.
For example, these columns will be identical, always:
-- assume that 'Calc' is a computed column equal to Salaray*.25
SELECT Calc, Salary*.25 Calc2 FROM YourTable
Also keep in mind that the persisted option doesn't change any of this. It keeps the value around which is nice for indexing, but the atomicity doesn't change.
Unfortunately not really, but a workaround that is sometimes worth it is
SELECT [calcval1], [calcval1] * .25 AS [calcval2]
FROM (SELECT [calcval1] = CASE Statement FROM whatever WHERE whatever)
Yes it's possible.
Use the WITH Statement for nested selects:
Two ways I can think of to do that. First understand that the calval1 column does not exist as far as SQL Server is concerned until the statement has run, therefore it cannot be directly used as showning your example. So you can put the calculation in there twice, once for calval1 and once as substitution for calcval1 in the calval2 calculation.
The other way is to make a derived table with calval1 in it and then calculate calval2 outside the derived table something like:
select calcval1*.25 as calval2, calval1, field1, field2
from (select casestament as cavlval1, field1, field2 from my table) a
You'll need to test both for performance.
You should use an outer apply instead of a subselect:
select V.calc,V.calc*0.25 from FOO outer apply (select case Statement as calc) V
You can't "reset" the value of a calculated column in a Select clause, if that's what you're trying to do... The value of a calculated column is based on the calculated column formulae. Which CAN include the value of another calculated column.... but you canlt reset the formulae in a Select clause... if all you want to do is "output" the value based on two calculated columns, (as the syntax in your question reads" Then the
"[calcval2]"
in
SELECT [calcval1] = CASE Statement, [calcval2] = [calcval1] * .25
would just become a column alias in the output of the Select Clause.
or are you asking how to define the formulae for one calculated column to be based on another?