Example of declaring and setting a SQL variable with cfqueryparam since there seems to be performance issues with large data sets when using cfqueryparam in a sub-select.

cf_cfqueryparamWithSQLVar

<cfset arguments.IsSold = 1>
<cfquery name="local.qryTraditional" datasource="cfartgallery">
	SELECT
		a1.ArtistID
		, a1.FirstName
		, a1.LastName
		, (
			SELECT TOP 1 LargeImage
			FROM Art
			WHERE IsSold = <cfqueryparam cfsqltype="cf_sql_bit" value="#arguments.IsSold#">
		) AS FirstSoldLargeImage
	FROM Artists a1
		INNER JOIN Art a2
			ON a1.ArtistID = a2.ArtistID
	WHERE 1 = 1
</cfquery>
<cfquery name="local.qryWithSQLVar" datasource="cfartgallery">
	DECLARE @IsSold AS BIT

	@IsSold = <cfqueryparam cfsqltype="cf_sql_bit" value="#arguments.IsSold#">

	SELECT
		a1.ArtistID
		, a1.FirstName
		, a1.LastName
		, (
			SELECT TOP 1 LargeImage
			FROM Art
			WHERE IsSold = @IsSold
		) AS FirstSoldLargeImage
	FROM Artists a1
		INNER JOIN Art a2
			ON a1.ArtistID = a2.ArtistID
	WHERE 1 = 1
</cfquery>