The optimization process and recommendations:

1. Create Optimal Indexes (modified query below): The recommended indexes are an integral part of this optimization effort and should be created before testing the execution duration of the optimized query.
2. Use Numeric Column Types For Numeric Values (query line: 14): Referencing a numeric value (e.g. 00) as a string in a WHERE clause might result in poor performance. Possible impacts of storing numbers as varchars: more space will be used, you won't be able to perform arithmetic operations, the data won't be self-validated, aggregation functions like SUM won't work, the output may sort incorrectly and more. If the column is numeric, remove the quotes from the constant value, to make sure a numeric comparison is done.
3. Use Numeric Column Types For Numeric Values (query line: 19): Referencing a numeric value (e.g. 0) as a string in a WHERE clause might result in poor performance. Possible impacts of storing numbers as varchars: more space will be used, you won't be able to perform arithmetic operations, the data won't be self-validated, aggregation functions like SUM won't work, the output may sort incorrectly and more. If the column is numeric, remove the quotes from the constant value, to make sure a numeric comparison is done.
4. Use Numeric Column Types For Numeric Values (query line: 24): Referencing a numeric value (e.g. 1100) as a string in a WHERE clause might result in poor performance. Possible impacts of storing numbers as varchars: more space will be used, you won't be able to perform arithmetic operations, the data won't be self-validated, aggregation functions like SUM won't work, the output may sort incorrectly and more. If the column is numeric, remove the quotes from the constant value, to make sure a numeric comparison is done.

Optimal indexes for this query:

CREATE INDEX clwh_data_idx_tran_date ON CLWH_COMMON_DATA (TRAN_DATE);
CREATE INDEX clwh_data_idx_netsw_acqeref ON CLWH_COMMON_DATA (NETSW_ACQEREF);

The optimized query:

SELECT
        "c"."NETSW_ACQEREF" AS "BANK",
        count("c"."NETSW_ACQEREF") AS "QTY",
        sum("c"."TRAN_AMNT") / 100 AS "AMOUNT",
        count(DISTINCT "c"."TERM_ID") AS "terminals" 
    FROM
        "CSCLWH"."CLWH_COMMON_DATA" "c" 
    WHERE
        (
            "c"."TRAN_DATE" BETWEEN 20201101 AND 20201111
        ) 
        AND (
            "c"."TRAN_TYPE" IN (
                '00', '01', '10', '12', '19', '20', '26', '29', '50', '51', '52'
            )
        ) 
        AND (
            "c"."RESP_CODE" IN (
                '0', '00', '000', '400'
            )
        ) 
        AND (
            "c"."MTI" IN (
                '1100', '1200', '1240', '1400', '1420'
            )
        ) 
    GROUP BY
        "c"."NETSW_ACQEREF" 
    ORDER BY
        "BANK"