## Bug description

The following filter fails with a 500 internal error.

![2021-02-04_12-07](https://user-images.githubusercontent.com/148820/106877644-a9f4ce80-66e1-11eb-8320-87bb213bdde2.png)


## Expected behavior

Error is shown to user about invalid regular expression.

Note no errors shown on the page as well.

## How to reproduce

1. Go to events
2. Add filter "Current URL matches regular expression ?*"
3. See infinite loading screen / error

## Environment

- [x] PostHog Cloud
- [x] self-hosted PostHog, version/commit: _please provide_

## Additional context

Note this can also happen when filtering by events.

#### *Thank you* for your bug report – we love squashing them!

ee/clickhouse/models/property.py
),
            params,
        )
    elif operator == "lt":
        params = {"k{}_{}".format(prepend, idx): prop.key, "v{}_{}".format(prepend, idx): prop.value}
        return (
            "AND toInt64OrNull(trim(BOTH '\"' FROM replaceRegexpAll({left}, ' ', ''))) < %(v{prepend}_{idx})s".format(
                idx=idx,
                prepend=prepend,
                left=denormalized
                if is_denormalized
                else "visitParamExtractRaw({prop_var}, %(k{prepend}_{idx})s)".format(
                    idx=idx, prepend=prepend, prop_var=prop_var,
                ),
            ),
            params,
        )
    else:
        if is_json(prop.value) and not is_denormalized:
            clause = "AND replaceRegexpAll(visitParamExtractRaw({prop_var}, %(k{prepend}_{idx})s),' ', '') = replaceRegexpAll(toString(%(v{prepend}_{idx})s),' ', '')"
        else:
            clause = "AND {left} = toString(%(v{prepend}_{idx})s)"
        params = {"k{}_{}".format(prepend, idx): prop.key, "v{}_{}".format(prepend, idx): prop.value}
        return (
            clause.format(
                left=denormalized if is_denormalized else json_extract, idx=idx, prepend=prepend, prop_var=prop_var
            ),
            params,
        )
def get_property_values_for_key(key: str, team: Team, value: Optional[str] = None):