Proper way to handle 'optional' where clause filters in SQL?

Question

Let\'s say you have a stored procedure, and it takes an optional parameter. You want to use this optional parameter in the SQL query. Typically this is how I\'ve seen it don

Answer 1

Change from using the "or" syntax to a two query approach, you'll see 2 different plans that should keep your logical read count as low as possible:

IF @MyOptionalParam is null
BEGIN

  SELECT *
  FROM dbo.MyTableName t1

END
ELSE
BEGIN

  SELECT *
  FROM dbo.MyTableName t1
  WHERE t1.MyField = @MyOptionalParam

END

You need to fight your programmer's urge to reduce duplication here. Realize you are asking for two fundamentally different execution plans and require two queries to produce two plans.