JSON Failure: not found on the data object for SharePoint Online column formatting

Question

I can't get SharePoint Online to recognize my field name. I know I could use @currentfield where I have [$2021_Q3] but I want to create a more complex formula and can't even get this basic one to work. Below is also the error I receive on the field

{
    "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
    "elmType": "div",
    "debugMode": true,
        "style":{
        "padding-left":"4px",
        "border-left-style": "solid",
        "border-left-width":"5px",
         "border-left-color":"=if([$2021_Q3]=='0','red','green')"
    },
    "attributes": {
        "class":"=if(@currentField==0,'sp-field-severity--severeWarning',if(@currentField==0,'sp-field-severity--warning','sp-field-severity--good'))"
    },
    "children": [
        {
            "elmType": "span",
            "attributes": {
                "iconName":"SortUp"
            }
        },
        {
            "elmType": "span",
            "txtContent":"@currentField"
        }
    ]
}

Answer 1

Fields must be referenced by their internal names. That is probably not the internal name of the 2021_Q3 column. If you entered it exactly like that the internal name is probably _x0032_021_Q3 so you would reference it in your format like this:

{
    "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
    "elmType": "div",
    "debugMode": true,
        "style":{
        "padding-left":"4px",
        "border-left-style": "solid",
        "border-left-width":"5px",
         "border-left-color":"=if([$_x0032_021_Q3]=='0','red','green')"
    },
    "attributes": {
        "class":"=if(@currentField==0,'sp-field-severity--severeWarning',if(@currentField==0,'sp-field-severity--warning','sp-field-severity--good'))"
    },
    "children": [
        {
            "elmType": "span",
            "attributes": {
                "iconName":"SortUp"
            }
        },
        {
            "elmType": "span",
            "txtContent":"@currentField"
        }
    ]
}

If that doesn't work, you can check your internal field name by going to List Settings and clicking on the column. In the URL the field will be listed at the end. Good luck!