Here is how i am using ISNULL condition to check for student address.
It works fine but how ISNULL function treat the null codition i.e the second parameter which is display if first condition is null.
Will it calculate Value for second parameter when first condition is not null?
select
...
...
(CASE
WHEN st.ADDRESS='Y' THEN st.LOCATION
ELSE
ISNULL(
(SELECT TOP 1 STDLOC.LOCATION FROM STDLOC
INNER JOIN COMLOC ON STKLOC.LOCATION=COMLOC.CODE AND COMLOC.ADDRESS='Y'
WHERE STDLOC.ZIBCODE=st.ZIBCODE)
,(SELECT TOP 1 COMLOC.LOCATION FROM COMLOC COMLOC.ZIBCODE=st.ZIBCODE))
END
) AS STDUDENTLOCATION
FROM STUDENT st
Both queries inside the ISNULL will be executed, even if the first query will return a value.
Here is a simple test I've made:
Create and populate sample table:
DECLARE #T AS TABLE
(
Col int
)
INSERT INTO #T Values(1),(2)
SELECT ISNULL(
(SELECT TOP 1 Col FROM #T ORDER BY Col DESC),
(SELECT TOP 1 Col FROM #T ORDER BY Col )
)
Execution plan image:
As you can clearly see, the execution plan includes both queries.
I also was looking for an answer. After some reading I came out with my own way to check it.
Deviding by zero will give an error, so we can try:
SELECT ISNULL( (SELECT TOP 1 object_id FROM sys.columns), 5 / 0)
This will give correct result. BUT
SELECT ISNULL( (SELECT TOP 0 object_id FROM sys.columns), 5 / 0)
It will throw an error, because result of first query gives NULL so it tries the second query which fails
ISNULL is a T-SQL specific function that will use the specified second parameter as the return value if the first parameter is NULL(https://msdn.microsoft.com/en-us/library/ms184325.aspx).
Use COALESCE function if you want to return the first non-null value from multiple arguments, and this is a standard function that is supported by all types of relational databases.
This POST provide a good answer for the question:
Is Sql Server's ISNULL() function lazy/short-circuited?
My question is not exactly but similar to this question
How to SELECT parts from a comma-separated field with a LIKE statement
but i have not seen any answer there. So I am posting my question again.
i have the following table
╔════════════╦═════════════╗
║ VacancyId ║ Media ║
╠════════════╬═════════════╣
║ 1 ║ 32,26,30 ║
║ 2 ║ 31, 25,20 ║
║ 3 ║ 21,32,23 ║
╚════════════╩═════════════╝
I want to select data who has media id=30 or media=21 or media= 40
So in this case the output will return the 1st and the third row.
How can I do that ?
I have tried media like '30' but that does not return any value. Plus i just dont need to search for one string in that field .
My database is SQL Server
Thank you
It's never good to use the comma separated values to store in database if it is feasible try to make separate tables to store them as most probably this is 1:n relationship.
If this is not feasible then there are following possible ways you can do this,
If your number of values to match are going to stay same, then you might want to do the series of Like statement along with OR/AND depending on your requirement.
Ex.-
WHERE
Media LIKE '%21%'
OR Media LIKE '%30%'
OR Media LIKE '%40%'
However above query will likely to catch all the values which contains 21 so even if columns with values like 1210,210 will also be returned. To overcome this you can do following trick which is hamper the performance as it uses functions in where clause and that goes against making Seargable queries.
But here it goes,
--Declare valueSearch variable first to value to match for you can do this for multiple values using multiple variables.
Declare #valueSearch = '21'
-- Then do the matching in where clause
WHERE
(',' + RTRIM(Media) + ',') LIKE '%,' + #valueSearch + ',%'
If the number of values to match are going to change then you might want to look into FullText Index and you should thinking about the same.
And if you decide to go with this after Fulltext Index you can do as below to get what you want,
Ex.-
WHERE
CONTAINS(Media, '"21" OR "30" OR "40"')
The best possible way i can suggest is first you have do comma separated value to table using This link and you will end up with table looks like below.
SELECT * FROM Table
WHERE Media in('30','28')
It will surely works.
You can use this, but the performance is inevitably poor. You should, as others have said, normalise this structure.
WHERE
',' + media + ',' LIKE '%,21,%'
OR ',' + media + ',' LIKE '%,30,%'
Etc, etc...
If you are certain that any Media value containing the string 30 will be one you wish to return, you just need to include wildcards in your LIKE statement:
SELECT *
FROM Table
WHERE Media LIKE '%30%'
Bear in mind though that this would also return a record with a Media value of 298,300,302 for example, so if this is problematic for you, you'll need to consider a more sophisticated method, like:
SELECT *
FROM Table
WHERE Media LIKE '%,30,%'
OR Media LIKE '30,%'
OR Media LIKE '%,30'
OR Media = '30'
If there might be spaces in the strings (as per in your question), you'll also want to strip these out:
SELECT *
FROM Table
WHERE REPLACE(Media,' ','') LIKE '%,30,%'
OR REPLACE(Media,' ','') LIKE '30,%'
OR REPLACE(Media,' ','') LIKE '%,30'
OR REPLACE(Media,' ','') = '30'
Edit: I actually prefer Coder of Code's solution to this:
SELECT *
FROM Table
WHERE ',' + LTRIM(RTRIM(REPLACE(Media,' ',''))) + ',' LIKE '%,30,%'
You mention that would wish to search for multiple strings in this field, which is also possible:
SELECT *
FROM Table
WHERE Media LIKE '%30%'
OR Media LIKE '%28%'
SELECT *
FROM Table
WHERE Media LIKE '%30%'
AND Media LIKE '%28%'
I agree not a good idea comma seperated values stored like that. Bu if you have to;
I think using inline function is will give better performance;
Select VacancyId, Media from (
Select 1 as VacancyId, '32,26,30' as Media
union all
Select 2, '31,25,20'
union all
Select 3, '21,32,23'
) asa
CROSS APPLY dbo.udf_StrToTable(Media, ',') tbl
where CAST(tbl.Result as int) in (30,21,40)
Group by VacancyId, Media
Output is;
VacancyId Media
----------- ---------
1 32,26,30
3 21,32,23
and our inline function script is;
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[udf_StrToTable]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].udf_StrToTable
GO
CREATE FUNCTION udf_StrToTable (#List NVARCHAR(MAX), #Delimiter NVARCHAR(1))
RETURNS TABLE
With Encryption
AS
RETURN
( WITH Split(stpos,endpos)
AS(
SELECT 0 AS stpos, CHARINDEX(#Delimiter,#List) AS endpos
UNION ALL
SELECT CAST(endpos+1 as int), CHARINDEX(#Delimiter,#List,endpos+1)
FROM Split
WHERE endpos > 0
)
SELECT ROW_NUMBER() OVER (ORDER BY (SELECT 1)) as inx,
SUBSTRING(#List,stpos,COALESCE(NULLIF(endpos,0),LEN(#List)+1)-stpos) Result
FROM Split
)
GO
This solution uses a RECURSIVE CTE to identify the position of each comma within the string then uses SUBSTRING to return all strings between the commas.
I've left some unnecessary code in place to help you get you head round what it's doing. You can strip it down to provide exactly what you need.
DROP TABLE #TMP
CREATE TABLE #TMP(ID INT, Vals CHAR(100))
INSERT INTO #TMP(ID,VALS)
VALUES
(1,'32,26,30')
,(2,'31, 25,20')
,(3,'21,32,23')
;WITH cte
AS
(
SELECT
ID
,VALS
,0 POS
,CHARINDEX(',',VALS,0) REM
FROM
#TMP
UNION ALL
SELECT ID,VALS,REM,CHARINDEX(',',VALS,REM+1)
FROM
cte c
WHERE CHARINDEX(',',VALS,REM+1) > 0
UNION ALL
SELECT ID,VALS,REM,LEN(VALS)
FROM
cte c
WHERE POS+1 < LEN(VALS) AND CHARINDEX(',',VALS,REM+1) = 0
)
,cte_Clean
AS
(
SELECT ID,CAST(REPLACE(LTRIM(RTRIM(SUBSTRING(VALS,POS+1,REM-POS))),',','') AS INT) AS VAL FROM cte
WHERE POS <> REM
)
SELECT
ID
FROM
cte_Clean
WHERE
VAL = 32
ORDER BY ID
I have two tables. One has an Order number, and details about the order:
CREATE TABLE #Order ( OrderID int )
and the second contains comments about the order:
CREATE TABLE #OrderComments ( OrderID int
Comment VarChar(500) )
Order ID Comments
~~~~~~~~ ~~~~~~~~
1 Loved this item!
1 Could use some work
1 I've had better
2 Try the veal
I'm tasked with determining the maximum length of the output, then returning output like the following:
Order ID Comments Length
~~~~~~~~ ~~~~~~~~ ~~~~~~
1 Loved this item! | Could use some work | I've had better 56
2 Try the veal 12
So, in this example, if this is all of the data, I'm looking for "56").
The main purpose is to determine the maximum length of all comments when appended together, including the | delimiter. This will be used when constructing the table this output will be put into, to determine if we can get the data within the 8,060 size limit for a row or if we need to use varchar(max) or text to hold the data.
I have tried a couple of subqueries that can generate this output to variables, but I haven't found one yet that could generate the above output. If I could get that, then I could just do a SELECT TOP 1 ... ORDER BY 3 DESC to get the number I'm looking for.
To find out what the length of the longest string will be if you trim and concatenate all the (not null) comments belonging to an OrderId with a delimiter of length three you can use
SELECT TOP(1) SUM(LEN(Comment)) + 3* (COUNT(Comment) - 1) AS Length
FROM OrderComments
GROUP BY OrderId
ORDER BY Length DESC
To actually do the concatenation you can use XML PATH as demonstrated in many other answers on this site.
WITH O AS
(
SELECT DISTINCT OrderID
FROM #Order
)
SELECT O.OrderID,
LEFT(y.Comments, LEN(y.Comments) - 1) AS Comments
FROM O
CROSS APPLY (SELECT ltrim(rtrim(Comment)) + ' | '
FROM #OrderComments oc
WHERE oc.OrderID = O.OrderID
AND Comment IS NOT NULL
FOR XML PATH(''), TYPE) x (Comments)
CROSS APPLY (SELECT x.Comments.value('.', 'VARCHAR(MAX)')) y(Comments)
All you need is STUFF function and XML PATH
Check out this sql fiddle
http://www.sqlfiddle.com/#!3/65cc6/5
I have a table where I am storing records with a Created_On date and a Last_Updated_On date. Each new record will be written with a Created_On, and each subsequent update writes a new row with the same Created_On, but an updated Last_Updated_On.
I am trying to design a query to return the newest row of each. What I have looks something like this:
SELECT
t1.[id] as id,
t1.[Store_Number] as storeNumber,
t1.[Date_Of_Inventory] as dateOfInventory,
t1.[Created_On] as createdOn,
t1.[Last_Updated_On] as lastUpdatedOn
FROM [UserData].[dbo].[StoreResponses] t1
JOIN (
SELECT
[Store_Number],
[Date_Of_Inventory],
MAX([Created_On]) co,
MAX([Last_Updated_On]) luo
FROM [UserData].[dbo].[StoreResponses]
GROUP BY [Store_Number],[Date_Of_Inventory]) t2
ON
t1.[Store_Number] = t2.[Store_Number]
AND t1.[Created_On] = t2.co
AND t1.[Last_Updated_On] = t2.luo
AND t1.[Date_Of_Inventory] = t2.[Date_Of_Inventory]
WHERE t1.[Store_Number] = 123
ORDER BY t1.[Created_On] ASC
The subselect works fine...I see X number of rows, grouped by Store_Number and Date_Of_Inventory, some of which have luo (Last_Updated_On) values of NULL. However, those rows in the sub-select where luo is null do not appear in the overall results. In other words, where I get 6 results in the sub-select, I only get 2 in the overall results, and its only those rows where the Last_Updated_On is not NULL.
So, as a test, I wrote the following:
SELECT 1 WHERE NULL = NULL
And got no results, but, when I run:
SELECT 1 WHERE 1 = 1
I get back a result of 1. Its as if SQL Server is not relating NULL to NULL.
How can I fix this? Why wouldn't two fields compare when both values are NULL?
You could use Coalesce (example assuming Store_Number is an integer)
ON
Coalesce(t1.[Store_Number],0) = Coalesce(t2.[Store_Number],0)
The ANSI Null comparison is not enabled by default; NULL doesn't equal NULL.
You can enable this (if your business case and your Database design usage of NULL requires this) by the Hint:
SET ansi_nulls off
Another alternative basic turn around using:
ON ((t1.[Store_Number] = t2.[Store_Number]) OR
(t1.[Store_Number] IS NULL AND t2.[Store_Number] IS NULL))
Executing your POC:
SET ansi_nulls off
SELECT 1 WHERE NULL = NULL
Returns:
1
This also works:
AND EXISTS (SELECT t1.Store_Number INTERSECT SELECT t2.Store_Number)
Hi I am currently doing a project in which the database needs to sort the lot numbers
prefix is nvarchar
lotnum is int
suffix is nvarchar
I have managed to convert the lot number
code i used is
Select (case when prefix is null then '' else prefix end) +
CONVERT ( nvarchar , ( lotnumber ) ) +(case when suffix is null then '' else suffix end)
(values in the database are a1a,1a,1,2,100)
when I order by lotnumber I get
a1a
1a
1
2
100
then prefix to the order by
and get this result
1
a1a
1a
2
100
I have added the suffix as well and returns the same result
I need to order it as follows
1
1a
2
100
a1a
Please could someone help me on this
Have you tried ordering by all three columns?
ORDER BY prefix, lotnum, suffix
By the way, I can see you're using SQL Server. To make things more portable, I'd recommend to use COALESCE and CAST instead of a CASE/WHEN and CONVERT for prefix and lotnum. Full query may look like this.
SELECT
COALESCE(prefix, '')
+ CAST(lotnum AS NVARCHAR)
+ COALESCE(suffix, '') AS lot_number
FROM
YourTable
ORDER BY
COALESCE(prefix, '')
,lotnum
,COALESCE(suffix, '')