def get_default_exprs(self, col, col_type):
        if col in self.col_blacklist:
            return {}
        d = {}
        d[(col, 'non_null')] = "COUNT({col})"
        if col_type in ['double', 'int', 'bigint', 'float', 'double']:
            d[(col, 'sum')] = 'SUM({col})'
            d[(col, 'min')] = 'MIN({col})'
            d[(col, 'max')] = 'MAX({col})'
            d[(col, 'avg')] = 'AVG({col})'
        elif col_type == 'boolean':
            d[(col, 'true')] = 'SUM(CASE WHEN {col} THEN 1 ELSE 0 END)'
            d[(col, 'false')] = 'SUM(CASE WHEN NOT {col} THEN 1 ELSE 0 END)'
        elif col_type in ['string']:
            d[(col, 'len')] = 'SUM(CAST(LENGTH({col}) AS BIGINT))'
            d[(col, 'approx_distinct')] = 'APPROX_DISTINCT({col})'

        return {k: v.format(col=col) for k, v in d.items()}
dataset/ETHPy150Open airbnb/airflow/airflow/operators/hive_stats_operator.py/HiveStatsCollectionOperator.get_default_exprs/original