SQL ignore part of WHERE if parameter is null

Question

I have a stored procedure that fetches info from a table based on 4 parameters.

I want to get values based on the parameters, but if a parameter is NULL then that pa

Answer 1

Add Condition in where and using CASE .. WHEN .. THEN..

TRY TO FOLLOWING WAY.

select col1,col2,...colN..from Table 
Where clm1 = CASE WHEN @PARAMETER = 0 THEN **COL1** ELSE **@PARAMETER** 

ONCE YOU SET SAME COLUMN NAME INTO WHERE CONDITION THEN YOU RETRIEVE ALL DATA FROM TABLE ELSE IF YOU WANT TO PASS AS PARAMETER THEN RETRIEVE BASE ON CONDITION VALUES FROM TABLE.

Answer 2

How about something like

SELECT Id, col1, col2, col3, col4 
FROM    myTable 
WHERE   col1 LIKE @Param1+'%'
OR      @Param1 IS NULL

in this specific case you could have also used

SELECT Id, col1, col2, col3, col4 
FROM    myTable 
WHERE   col1 LIKE ISNULL(@Param1,'')+'%'

But in general you can try something like

SELECT Id, col1, col2, col3, col4 
FROM    myTable 
WHERE   (condition1 OR @Param1 IS NULL)
AND     (condition2 OR @Param2 IS NULL)
AND     (condition3 OR @Param3 IS NULL)
...
AND     (conditionN OR @ParamN IS NULL)

Answer 3

CREATE PROCEDURE myProcedure
  @Param1 nvarchar(50) **= '',**              //#1
  @Param2 nvarchar(50) **= '',**
  @Param3 nvarchar(50) **= '',**
  @Param4 nvarchar(50) **= ''**
AS
BEGIN
    **SET @Param1 = ISNULL(@Param1, '')**     //#2

    SELECT Id, col1, col2, col3, col4 FROM myTable WHERE col1 LIKE @Param1+'%' 
END

1. Give default value(empty string '' ) to your params: If caller skip passing these params you will receive an empty string that will work fine with your like clause (ex. myProcedure @Param4 = 'some value' // in this case other parameters will be set to empty string('') @param1 )
2. Set params to '' to save yourself from null parameters(ex. myProcedure Param1 = null, @param2 = null ... // in this case like won't work on the null values and will give you no record against the parameter, to avoid that do an additional check for null value.

Answer 4

CREATE PROCEDURE myProcedure
    @Param1 nvarchar(50),
    @Param2 nvarchar(50),
    @Param3 nvarchar(50),
    @Param4 nvarchar(50)
AS
BEGIN
    IF(@Param1 IS NULL)
        BEGIN
            SELECT Id, col1, col2, col3, col4 FROM myTable
        END
    ELSE
        BEGIN
            SELECT Id, col1, col2, col3, col4 FROM myTable WHERE col1 LIKE @Param1+'%' OR @Param1 is Null
        END
END

This should help

regards

Ashutosh Arya

Answer 5

This will work and easier to understand, at least for me. The IIF statement is only available in SQL Server 2012 and up, you can replace it with a case statement.

SELECT Id, col1, col2, ... 
FROM    myTable 
WHERE   condition1 = IIF(col1 IS NULL, col1, @Param1)
AND     condition2 = IIF(col2 IS NULL, col2, @Param2)...

Answer 6

If you mean @param1 is parameter for col1, @param2 is parameter for col2,... etc You can try this:

CREATE PROCEDURE myProcedure
@Param1 nvarchar(50),
@Param2 nvarchar(50),
@Param3 nvarchar(50),
@Param4 nvarchar(50)
AS
BEGIN
declare @query nvarchar(4000)
SET @query='SELECT Id, col1, col2, col3, col4 FROM myTable '+
    (case when ((@Param1 is null) and (@Param2 is null) and (@Param3 is null) and (@Param4 is null))
    then ''
    else
        'where '+
        (case when @Param1 is not null
        then ' col1 like '''+@param1+'%'''+
            (case when @param2 is not null then ' AND ' else '' end)
        else '' end)+
        (case when @Param2 is not null
        then ' col2 like '''+@param2+'%'''+
            (case when @param3 is not null then ' AND ' else '' end)
        else '' end)+
        (case when @Param3 is not null
        then ' col3 like '''+@param3+'%'''+
            (case when @param4 is not null then ' AND ' else '' end)
        else '' end)+
        (case when @Param4 is not null
        then ' col4 like '''+@param4+'%'''
        else '' end)
    end)

exec sp_sqlexec @query