Small update to QueryAppend to prevent NULL values (dates & numbers) from being incorrectly recast to an invalid "empty string" by ColdFusion's Query-of-Queries.

QueryAppendUDF.cfm

<!--- 7/5/2006 QueryAppend By Ben Nadel https://www.bennadel.com/blog/114-coldfusion-queryappend-qone-qtwo.htm
      1/5/2017 New "EmptyAsNull" option to prevent NULL values (dates & numbers) from being incorrectly recast
      to an invalid "empty string" by ColdFusion's Query-of-Queries and throwing "Error casting an object
      of type to an incompatible type" error. --->
<cffunction name="QueryAppend" access="public" returntype="void" output="false" hint="This takes two queries and appends the second one to the first one. This actually updates the first query and does not return anything.">
	<cfargument name="QueryOne" type="query" required="true">
	<cfargument name="QueryTwo" type="query" required="true">
	<cfargument name="EmptyAsNull" default="" required="false"> 
	<cfset var LOCAL = StructNew()>
	<cfset LOCAL.Columns = ListToArray(ARGUMENTS.QueryOne.ColumnList)>
	<cfset LOCAL.EmptyAsNull = 0>
	<cfif isValid("boolean", ARGUMENTS.EmptyAsNull) AND ARGUMENTS.EmptyAsNull>
		<cfset LOCAL.EmptyAsNull = 1>
	</cfif>
	<cfloop query="ARGUMENTS.QueryTwo">
		<cfset QueryAddRow(ARGUMENTS.QueryOne)>
		<cfloop ARRAY="#LOCAL.Columns#" index="LOCAL.ColumnName">
			<cfif StructKeyExists(ARGUMENTS.QueryTwo, LOCAL.ColumnName) AND (NOT LOCAL.EmptyAsNull OR LEN(ARGUMENTS.QueryTwo[LOCAL.ColumnName][ARGUMENTS.QueryTwo.CurrentRow]))>
				<cfset ARGUMENTS.QueryOne[LOCAL.ColumnName][ARGUMENTS.QueryOne.RecordCount] = ARGUMENTS.QueryTwo[LOCAL.ColumnName][ARGUMENTS.QueryTwo.CurrentRow]>
			</cfif>
		</cfloop>
	</cfloop>
	<cfreturn>
</cffunction>