Perspective Properties - Value error

I got this caution while binding a query to this property. As I binded the expected datatype "Integer". But it is showing the expected error "string found" . how to resolve this

Show us your binding. (If it's an expression then please post </> formatted code rather than a picture of code.)

Its a Query Binding

Select Top 1   PF from  Main WHERE  BG =:bg and Plant =:pl and Line=:ll  and Machine =:ma and
Date between :st and :sp
order by Date desc
    "type": "ia.chart.simple-gauge",
    "version": 0,
    "props": {
      "minValue": -2,
      "maxValue": 1,
      "startAngle": 0,
      "arc": {
        "color": "#008000"
      "arcBackground": {
        "color": "#008000"
      "label": {
        "visible": false
      "animate": true,
      "style": {
        "classes": []
    "meta": {
      "name": "SimpleGauge"
    "position": {
      "basis": "300px"
    "custom": {},
    "propConfig": {
      "props.value": {
        "binding": {
          "type": "query",
          "config": {
            "returnFormat": "scalar",
            "queryPath": "Online_PF",
            "parameters": {
              "ll": "{..../Line_Dropdown.props.value}",
              "st": "{..../DateTimeInput.props.value}",
              "ma": "{..../Machine_Dropdown.props.value}",
              "bg": "{view.params.BG}",
              "pl": "{view.params.Plant}",
              "sp": "dateArithmetic({..../DateTimeInput.props.value}, 1, \"days\")"

What data type is the database field PF? If it's a string or text then that's probably your problem.
I can reproduce the error by creating an expression binding with the simple expression "-0.99" which, of course, is a string.

If you can't fix the DB then try adding an expression transform on the binding.

Thanks for the suggestions.I have added the Expression transform. Now it works well.

Or change the query, which would be a touch more performant:

SELECT Top 1 CAST(PF as float)
FROM  Main 
WHERE  BG =:bg 
   AND Plant =:pl 
   AND Line=:ll  
   AND Machine =:ma
   AND Date BETWEEN :st AND :sp