/* I've replaced the hard-coded date with 'today()' so I can capture updates to the first 
 * data entity first and use the resulting 'ids' to query the second table for updates.
 * As I suspected, I get an error if the first query results in an 'empty set'
 * I get "Expression evaluation error: Invalid index: Cannot index property "id" of type Text into type List of Variant"
 * I've tried several if() statements to check for null values but I keep getting the same error. Ugh!
 

with(

local!checkIds: fn!index(a!queryEntity(
  entity: cons!ABC_CHECK_DS,
  query: a!query(
    selection: {},
    logicalExpression: a!queryLogicalExpression(
      operator: "OR",
      filters: {
        a!queryFilter(
          field: "effectiveDateTime",
          operator: ">=",
          value: todatetime(today())
        )
      }
    ),
    pagingInfo: a!pagingInfo(
      startIndex: 1, 
      batchSize: -1,
      sort: a!sortInfo(
        field: "id",
        ascending: true
      )
      )
    )      
  ).data,"id",null),

  local!entities: a!queryEntity(
  entity: cons!ABC_AMOUNT_DS,
  query: a!query(
    filter: if(
          rule!APN_isEmpty(local!checkIds),
          null,
          a!queryFilter(
            field:"checkid",
            operator:"in",
            value: tointeger(local!voidedcheckIds)
          )
        )
	   ),
    pagingInfo: a!pagingInfo(
      startIndex: 1, 
      batchSize: -1
     )
    )
   ).data,

  /*
  * Construct an HTTP response that contains the information that we just stored
  * in "local!entities".
  */
  a!httpResponse(
    /*
    * Set an HTTP header that tells the client that the body of the response
    * will be JSON-encoded.
    */
    headers: {
      a!httpHeader(name: "content-type", value: "application/json")
    },
    /*
    * JSON-encode the value of "local!entities" and place it in the response body.
    */
    body: a!toJson(value: local!entities)
  )
)