case sqlparser.IsNotNullStr:
return elastic.NewExistsQuery(colName), nil
// This should be impossible since the query parser only calls this function with one of those
// operators strings.
return nil, query.NewConverterError(
"%s: 'IS' operator can only be used as 'IS NULL' or 'IS NOT NULL'",
query.InvalidExpressionErrMessage,
)
}
}