I have an application on a SQL Server 2008 database. This database has a stored procedure that queries one of the tables. This stored procedure takes two parameters: userName and ID
The userName parameter will always be passed. However, the ID field will either be NULL or an actual value. If the value is something other than NULL, I need to consider it in the WHERE clause of my query. Unfortunately, I'm not positive how to do this. Currently, I'm trying
SELECT
*
FROM
TaskTicket t
WHERE
t.[UserName]=#userName AND
-- This is where I am stumped
Thank you for your help!
SELECT
*
FROM
TaskTicket t
WHERE
t.[UserName]=#userName
AND (#ID IS NULL OR t.[ID] = #ID)
Try this:
SELECT
*
FROM
TaskTicket t
WHERE
t.[UserName]=#userName AND
(#ID is null
or -- replace this comment with your logic
)
Group the conditionals together
select *
from TaskTicket t
Where t.[UserName]=#userName AND
((t.Id is null and (conditions_when_id_is_null))
or
(t.Id is not null and (conditions_when_id_is_not_null)))
SELECT
<column list>
FROM
TaskTicket T
WHERE
T.[UserName] = #username AND
(T.id = #id OR #id IS NULL)
Just be aware that this may cause a non-optimal query plan in some cases. That's probably not a big deal in this case unless your table is huge and you don't have an index on UserName and ID.
Hopefully more efficient than using an OR condition:
SELECT
*
FROM
TaskTicket t
WHERE
t.[UserName]=#userName AND
t.[ID] LIKE COALESCE(#ID,'%')
NB: will only work if ID is a non-NULLable, character field. (You can use CAST and COALESCE on t.[ID] otherwise, but then it's unlikely to be more efficient than an OR condition.)
Alternatively, use dynamic SQL in your stored procedure to completely omit the t.[ID] condition, if #ID is NULL.
declare #SQL nvarchar(max)
declare #WHERE_ID nvarchar(20)
set #WHERE_ID =
(
CASE
WHEN #ID is null THEN ''
ELSE ' AND ID = ' + CAST(#ID as nvarchar(10))
END
)
set #SQL = 'SELECT * FROM TaskTicket WHERE UserName = ' + #userName + #WHERE_ID
EXEC #SQL
Create procedure Procedure1
(
#Param1 nvarchar(100)=null,
)
AS
BEGIN
SELECT
ColumnName1,ColumneName2
FROM TableName
WHERE
(#Param1 IS NULL OR ColumnName1=#Param1)
END
Related
I am stuck at a point.
I want to select based on the column entitytype if entitytype value is Booking or JOb then it will filter on its basis but if it is null or empty string('') then i want it to return all the rows containing jobs and bookings
create proc spproc
#entityType varchar(50)
as
begin
SELECT TOP 1000 [Id]
,[EntityId]
,[EntityType]
,[TenantId]
FROM [FutureTrakProd].[dbo].[Activities]
where TenantId=1 and EntityType= case #EntityType when 'BOOKING' then 'BOOKING'
when 'JOB' then 'JOB'
END
end
Any help would be appreciable
Thankyou
create proc spproc
#entityType varchar(50)
as
begin
SELECT TOP 1000 [Id]
,[EntityId]
,[EntityType]
,[TenantId]
FROM [FutureTrakProd].[dbo].[Activities]
where TenantId=1 and (#EntityType is null OR EntityType= #EntityType)
end
You don't need to use case expression you can do :
SELECT TOP 1000 [Id], [EntityId], [EntityType], [TenantId]
from [FutureTrakProd].[dbo].[Activities]
WHERE TenantId = 1 AND
(#EntityType IS NULL OR EntityType = #EntityType)
ORDER BY id; -- whatever order you want (asc/desc)
For your query procedure you need to state explicit ORDER BY clause otherwise TOP 1000 will give random Ids.
You don't need a CASE expression for this, you just need an OR. The following should put you on the right path:
WHERE TenantId=1
AND (EntityType = #EntityType OR #EntityType IS NULL)
Also, note it would also be wise to declare your parameter as NULLable:
CREATE PROC spproc #entityType varchar(50) = NULL
This means that someone can simply exclude the paramter, value than having to pass NULL (thus EXEc spproc; would work).
Finally, if you're going to have lots of NULLable parameters, then you're looking at a "catch-all" query; the solution would be different if that is the case. "Catch-all" queries can be notoriously slow.
You can execute a dynamic sql query.
Query
create proc spproc
#entityType varchar(50)
as
begin
declare #sql as nvarchar(max);
declare #condition as nvarchar(2000);
select = case when #entityType is not null then ' and [EntityType] = #entityType;' else ';' end;
select #sql = 'SELECT TOP 1000 [Id], [EntityId], [EntityType], [TenantId] FROM [FutureTrakProd].[dbo].[Activities] where TenantId = 1 ';
exec sp_executesql #sql,
N'#entityType nvarchar(1000)',
#entityType = #entityType
end
I want to select records from a table in a stored procedure. Given parameters can be empty or a string including some keys separated by comma (1, 2, etc)
I want to manage that when a parameter is an empty string, "WHERE" ignore searching.
I'm using this code:
where (CASE when #PatientID <> 0 then ( dental.ID_Sick in (1,2)) else (1=1) end)
Something like that is working in W3School. I mean:
SELECT * FROM Customers
WHERE (case when 1=1 then (Country IN ('Germany', 'France', 'UK')) else 1=1 end);
What is the problem in my query that does not work? SQLServerManagementStudio is giving error on "IN" statement.
Solution:
The best way to handle such optional parameters is to use dynamic SQL and built the query on the fly. Something like....
CREATE PROCEDURE myProc
#Param1 VARCHAR(100) = NULL
,#Param2 VARCHAR(100) = NULL
,#Param3 VARCHAR(100) = NULL
,#ListParam VARCHAR(100) = NULL
--, etc etc...
AS
BEGIN
SET NOCOUNT ON;
Declare #Sql NVARCHAR(MAX);
SET #Sql = N' SELECT *
FROM TableName
WHERE 1 = 1 '
-- add in where clause only if a value was passed to parameter
+ CASE WHEN #Param1 IS NOT NULL THEN
N' AND SomeColumn = #Param1 ' ELSE N'' END
-- add in where clause a different variable
-- only if a value was passed to different parameter
+ CASE WHEN #Param2 IS NOT NULL THEN
N' AND SomeOtherColumn = #Param3 ' ELSE N'' END
-- List Parameter used with IN clause if a value is passed
+ CASE WHEN #ListParam IS NOT NULL THEN
N' AND SomeOtherColumn IN (
SELECT Split.a.value(''.'', ''VARCHAR(100)'') IDs
FROM (
SELECT Cast (''<X>''
+ Replace(#ListParam, '','', ''</X><X>'')
+ ''</X>'' AS XML) AS Data
) AS t CROSS APPLY Data.nodes (''/X'') AS Split(a) '
ELSE N'' END
Exec sp_executesql #sql
, N' #Param1 VARCHAR(100), #Param2 VARCHAR(100) ,#Param3 VARCHAR(100) ,#ListParam VARCHAR(100)'
, #Param1
, #Param2
,#Param3
, #ListParam
END
Problem with Other approach
There is a major issue with this other approach, you write your where clause something like...
WHERE ( ColumnName = #Parameter OR #Parameter IS NULL)
The Two major issues with this approach
1) you cannot force SQL Server to check evaluate an expression first like if #Parameter IS NULL, Sql Server might decide to evaluate first the expression ColumnName = #Parameterso you will have where clause being evaluated even if the variable value is null.
2) SQL Server does not do Short-Circuiting (Like C#), even if it decides to check the #Parameter IS NULL expression first and even if it evaluates to true, SQL Server still may go ahead and evaluating other expression in OR clause.
Therefore stick to Dynamic Sql for queries like this. and happy days.
SQL Server does not have a Bool datatype, so you can't assign or return the result of a comparison as a Bool as you would in other languages. A comparison can only be used with IF-statements or WHERE-clauses, or in the WHEN-part of a CASE...WHEN but not anywhere else.
Your specific example would become this:
SELECT * FROM Customers
WHERE 1=1 OR Country IN ('Germany', 'France', 'UK')
It would be better readable to rewrite your statement as follows:
WHERE #PatientID = 0
OR dental.ID_Sick in (1,2)
Referring to your actual question, I'd advise to read the linked question as provided by B House.
May be this straight way will work for you
IF (#PatientID <> 0)
BEGIN
SELECT * FROM Customers
WHERE Country IN ('Germany', 'France', 'UK')
END
try this:
WHERE 1=(CASE WHEN #PatientID <>0 AND dental.ID_Sick in (1,2) THEN 1
WHEN #PatientID =0 THEN 1
ELSE 0
END)
I need to EXEC a stored procedure which requires a COALESCE if a field value is null use another field value.
EXEC dbo.TestSproc COALESCE ('Field1','Field2')
Would anyone be able to advise on how best to code this?
This will be called in a SQL Job so needs to be one line.
Alternatively:
declare #field1 bigint = (select Field1 from table1);
declare #field2 bigint = (select Field2 from table2);
declare #isnull bigint = isnull(#field1, #field2);
exec dbo.TestSproc #isnull
CASE statement for when that field us NULL
CASE WHEN field IS NULL
THEN COALESCE ('Field1','Field2')
ELSE 0 END
Please tell me if this isn't the right way to approach the problem.
I want to declare the code after my AND condition in a variable.. the code is:
SELECT * FROM MyTable
WHERE Key = '12345'
AND (Condition1 or Condition2 or Condition3)
I am hoping to achieve something like this:
DECLARE #Condition
SET #Condition = 'Condition1 or Condition2 or Condition3'
SELECT * FROM MyTable
WHERE Key = '12345'
AND #Condition
The AND operator expects a boolean expresssion so this doesn't work. Please tell me how I can achieve this..
The idea is that I can store the #Condition in a variable table (varName, varValue) and fetch it from there whenever I want to use it in the code (kinda like a global variable). Please also let me know if the performance of the code will be affected if I follow this approach.
You need to use dynamic sql:
declare #sql nvarchar(max);
set #sql = 'select * from mytable where [key] = #key and #condition';
set #sql = replace(#sql, '#condition', #condition);
exec sp_executesql #sql, N'#key varchar(255)', #key = '12345';
When you put #condition in the where clause it is treated as a string. That's all. No semantic analysis.
I'm wondering if you can create a table variable with your conditions... Since you're not very specific about what those conditions are, it's hard to tell if something like this would work, but this is an approach I sometimes use:
declare #conditions table (condition nvarchar(255), value bit);
insert into #table (condition, value)
select condition, value
from (
values ('Less than x', 1), ('Greater than y', 0))
) x (condition, value)
Then use that in your where clause...
select *
from Table
where not exists (select 1 from #conditions where value = 1)
Or you can join onto it. If you are comparing ints, you could cross join and say where #conditions.condition < yourTable.value.
This may be obvious but I'm getting very confused.
I have an SQL query with a where clause (where in with a list of parameters). If all of these parameters are null, I need the SQL to ignore the where clause and retrieve all the records. Is this easy to do in SQL? I know one way around it is to just remove the where clause using code if the parameters are null.
You could try do something like this:
select *
from foo
where (#parameter1 is null AND #parameter2 is null)
OR (#parameter1 = 'value1'
AND
#parameter2 = 'value2')
Offcourse it needs a bit of tuning in your own query, but now you will check if the parameters are null or do your original where-clause.
The most performant way is to not include the WHERE clause at all if that's an option for you.
You often see tricks such as WHERE X=#X OR #X IS NULL used but these can lead to sub optimal plans and unnecessary table scans in the event you are passing a specific value for #X
Edit:
As this answer seems to have met with some unexpected scepticism...
create table #t
(
id varchar(5) primary key /*varchar to test LIKE without causing any casts*/
)
INSERT INTO #t
SELECT ROW_NUMBER() OVER (ORDER BY (SELECT 0))
FROM sys.all_columns
SET STATISTICS IO ON
/*Test the equals */
EXEC sp_executesql N'
SELECT *
FROM #t
WHERE (#id IS NULL OR id = #id)', N'#id varchar(5)', #id='1'
/*Is `LIKE` any better? */
EXEC sp_executesql N'
SELECT *
FROM #t
WHERE (#id IS NULL OR id LIKE #id)', N'#id varchar(5)', #id='1'
/*What should the plan look like? */
EXEC sp_executesql N'
SELECT *
FROM #t
WHERE (id = #id)', N'#id varchar(5)', #id='1'
DROP TABLE #t
if it's a stored procedure, either you do with dynamic SQL and do not append the where clause at all if parameters are null, or you still use an IF ELSE and write the query twice in the IF and in the else one with the where and one without, I agree with Martin that the where should be fully avoided if all records should be retrieved.
...
WHERE
(
col1 IS NULL
AND col2 IS NULL
AND col3 IS NULL
) OR
(
conditions...
);
i really think this will work
Where ((CASE WHEN #Parameter1 is null then 1 else 0 end) = 1 and
(CASE WHEN #Parameter2 is null then 1 else 0 end) = 1)
Have a look here handling-optional-parameters for an article fitting your requirements. The article compares various ways of doing optional parameters and discusses different versions of SQL Server as well as the performance of each.
I think what you are after is an individual IS NULL + OR per column, right?
WHERE (#col1 IS NULL OR col1 LIKE #col1)
AND (#col2 IS NULL OR col2 = #col2)