How can I use optional parameters in a T-SQL stored procedure?

The answer from @KM is good as far as it goes but fails to fully follow up on one of his early bits of advice;

..., ignore compact code, ignore worrying about repeating code, ...

If you are looking to achieve the best performance then you should write a bespoke query for each possible combination of optional criteria. This might sound extreme, and if you have a lot of optional criteria then it might be, but performance is often a trade-off between effort and results. In practice, there might be a common set of parameter combinations that can be targeted with bespoke queries, then a generic query (as per the other answers) for all other combinations.

CREATE PROCEDURE spDoSearch @FirstName varchar(25) = null, @LastName varchar(25) = null, @Title varchar(25) = null AS BEGIN IF (@FirstName IS NOT NULL AND @LastName IS NULL AND @Title IS NULL) -- Search by first name only SELECT ID, FirstName, LastName, Title FROM tblUsers WHERE FirstName = @FirstName ELSE IF (@FirstName IS NULL AND @LastName IS NOT NULL AND @Title IS NULL) -- Search by last name only SELECT ID, FirstName, LastName, Title FROM tblUsers WHERE LastName = @LastName ELSE IF (@FirstName IS NULL AND @LastName IS NULL AND @Title IS NOT NULL) -- Search by title only SELECT ID, FirstName, LastName, Title FROM tblUsers WHERE Title = @Title ELSE IF (@FirstName IS NOT NULL AND @LastName IS NOT NULL AND @Title IS NULL) -- Search by first and last name SELECT ID, FirstName, LastName, Title FROM tblUsers WHERE FirstName = @FirstName AND LastName = @LastName ELSE -- Search by any other combination SELECT ID, FirstName, LastName, Title FROM tblUsers WHERE (@FirstName IS NULL OR (FirstName = @FirstName)) AND (@LastName IS NULL OR (LastName = @LastName )) AND (@Title IS NULL OR (Title = @Title )) END 

The advantage of this approach is that in the common cases handled by bespoke queries the query is as efficient as it can be - there's no impact by the unsupplied criteria. Also, indexes and other performance enhancements can be targeted at specific bespoke queries rather than trying to satisfy all possible situations.

You can do in the following case,

CREATE PROCEDURE spDoSearch @FirstName varchar(25) = null, @LastName varchar(25) = null, @Title varchar(25) = null AS BEGIN SELECT ID, FirstName, LastName, Title FROM tblUsers WHERE (@FirstName IS NULL OR FirstName = @FirstName) AND (@LastNameName IS NULL OR LastName = @LastName) AND (@Title IS NULL OR Title = @Title) END 

however depend on data sometimes better create dynamic query and execute them.

Five years late to the party.

It is mentioned in the provided links of the accepted answer, but I think it deserves an explicit answer on SO - dynamically building the query based on provided parameters. E.g.:

Setup

-- drop table Person create table Person ( PersonId INT NOT NULL IDENTITY(1, 1) CONSTRAINT PK_Person PRIMARY KEY, FirstName NVARCHAR(64) NOT NULL, LastName NVARCHAR(64) NOT NULL, Title NVARCHAR(64) NULL ) GO INSERT INTO Person (FirstName, LastName, Title) VALUES ('Dick', 'Ormsby', 'Mr'), ('Serena', 'Kroeger', 'Ms'), ('Marina', 'Losoya', 'Mrs'), ('Shakita', 'Grate', 'Ms'), ('Bethann', 'Zellner', 'Ms'), ('Dexter', 'Shaw', 'Mr'), ('Zona', 'Halligan', 'Ms'), ('Fiona', 'Cassity', 'Ms'), ('Sherron', 'Janowski', 'Ms'), ('Melinda', 'Cormier', 'Ms') GO 

Procedure

ALTER PROCEDURE spDoSearch @FirstName varchar(64) = null, @LastName varchar(64) = null, @Title varchar(64) = null, @TopCount INT = 100 AS BEGIN DECLARE @SQL NVARCHAR(4000) = ' SELECT TOP ' + CAST(@TopCount AS VARCHAR) + ' * FROM Person WHERE 1 = 1' PRINT @SQL IF (@FirstName IS NOT NULL) SET @SQL = @SQL + ' AND FirstName = @FirstName' IF (@LastName IS NOT NULL) SET @SQL = @SQL + ' AND FirstName = @LastName' IF (@Title IS NOT NULL) SET @SQL = @SQL + ' AND Title = @Title' EXEC sp_executesql @SQL, N'@TopCount INT, @FirstName varchar(25), @LastName varchar(25), @Title varchar(64)', @TopCount, @FirstName, @LastName, @Title END GO 

Usage

exec spDoSearch @TopCount = 3 exec spDoSearch @FirstName = 'Dick' 

Pros:

• easy to write and understand
• flexibility - easily generate the query for trickier filterings (e.g. dynamic TOP)

Cons:

• possible performance problems depending on provided parameters, indexes and data volume

Not direct answer, but related to the problem aka the big picture

Usually, these filtering stored procedures do not float around, but are being called from some service layer. This leaves the option of moving away business logic (filtering) from SQL to service layer.

One example is using LINQ2SQL to generate the query based on provided filters:

 public IList<SomeServiceModel> GetServiceModels(CustomFilter filters) { var query = DataAccess.SomeRepository.AllNoTracking; // partial and insensitive search if (!string.IsNullOrWhiteSpace(filters.SomeName)) query = query.Where(item => item.SomeName.IndexOf(filters.SomeName, StringComparison.OrdinalIgnoreCase) != -1); // filter by multiple selection if ((filters.CreatedByList?.Count ?? 0) > 0) query = query.Where(item => filters.CreatedByList.Contains(item.CreatedById)); if (filters.EnabledOnly) query = query.Where(item => item.IsEnabled); var modelList = query.ToList(); var serviceModelList = MappingService.MapEx<SomeDataModel, SomeServiceModel>(modelList); return serviceModelList; } 

Pros:

• dynamically generated query based on provided filters. No parameter sniffing or recompile hints needed
• somewhat easier to write for those in the OOP world
• typically performance friendly, since "simple" queries will be issued (appropriate indexes are still needed though)

Cons:

• LINQ2QL limitations may be reached and forcing a downgrade to LINQ2Objects or going back to pure SQL solution depending on the case
• careless writing of LINQ might generate awful queries (or many queries, if navigation properties loaded)

Extend your WHERE condition:

WHERE (FirstName = ISNULL(@FirstName, FirstName) OR COALESCE(@FirstName, FirstName, '') = '') AND (LastName = ISNULL(@LastName, LastName) OR COALESCE(@LastName, LastName, '') = '') AND (Title = ISNULL(@Title, Title) OR COALESCE(@Title, Title, '') = '') 

i. e. combine different cases with boolean conditions.