TO_BOOLEAN

Converts an input value to a boolean value.The input can be a single- or multi-valued field or an expression. The input
type must be of a string or numeric type.A string value of "true" will be case-insensitive converted to the Boolean
true. For anything else, including the empty string, the function will
return false. For example:
```esql
ROW str = ["true", "TRuE", "false", "", "yes", "1"]
| EVAL bool = TO_BOOLEAN(str)
```

The numerical value of 0 will be converted to false, anything else will be
converted to true.Alias: TO_BOOL