Q22
select 
    substr(c_phone, 1, 2) as cntrycode, 
    count(*) as numcust, 
    sum(c_acctbal) as totacctbal 
from 
    customer 
where 
    substr(c_phone, 1, 2) in ('13', '31', '23', '29', '30', '18', '17') 
    and c_acctbal > (
        select 
            avg(c_acctbal) 
        from 
            customer 
        where 
            c_acctbal > 0.00 
            and substr(c_phone, 1, 2) in ('13', '31', '23', '29', '30', '18', '17')) 
            and not exists (
                select 
                    * 
                from 
                    orders 
                where 
                    o_custkey = c_custkey
              )
         group by 
            substr(c_phone, 1, 2) 
         order by 
            cntrycode;

Oracle Execution Plan

Operation: table access
Options: FULL
Object_type: TABLE
Other: 
Object_owner: CALUSER01
Search_columns: 
Projection: C_ACCTBAL
Object_name: CUSTOMER
Alias: CUSTOMER@SEL$2
Extended_information:    FP:C_ACCTBAL>0.00 AND (SUBSTR(C_PHONE,1,2)='13' OR SUBSTR(C_PHONE,1,2)='31' OR SUBSTR(C_PHONE,1,2)='23' OR SUBSTR(C_PHONE,1,2)='29' OR SUBSTR(C_PHONE,1,2)='30' OR SUBSTR(C_PHONE,1,2)='18' OR SUBSTR(C_PHONE,1,2)='17')
Access_predicates: 
Filter_predicates: C_ACCTBAL>0.00&(SUBSTR(C_PHONE,1,2)='13'|SUBSTR(C_PHONE,1,2)='31'|SUBSTR(C_PHONE,1,2)='23'|SUBSTR(C_PHONE,1,2)='29'|SUBSTR(C_PHONE,1,2)='30'|SUBSTR(C_PHONE,1,2)='18'|SUBSTR(C_PHONE,1,2)='17')
Select_level: SEL$2
--------------------
Operation: sort
Options: AGGREGATE
Object_type: 
Other: 
Object_owner: 
Search_columns: 
Projection:  AVG(C_ACCTBAL)
Object_name: 
Alias: 
Extended_information: 
Access_predicates: 
Filter_predicates: 
Select_level: SEL$2
--------------------
Operation: table access
Options: FULL
Object_type: TABLE
Other: 
Object_owner: CALUSER01
Search_columns: 
Projection: C_CUSTKEY^C_PHONE^C_ACCTBAL
Object_name: CUSTOMER
Alias: CUSTOMER@SEL$1
Extended_information:    FP:(SUBSTR(C_PHONE,1,2)='13' OR SUBSTR(C_PHONE,1,2)='31' OR SUBSTR(C_PHONE,1,2)='23' OR SUBSTR(C_PHONE,1,2)='29' OR SUBSTR(C_PHONE,1,2)='30' OR SUBSTR(C_PHONE,1,2)='18' OR SUBSTR(C_PHONE,1,2)='17') AND C_ACCTBAL> (SELECT AVG(C_ACCTBAL) FROM CUSTOMER CUSTOMER WHERE C_ACCTBAL>0.00 AND (SUBSTR(C_PHONE,1,2)='13' OR SUBSTR(C_PHONE,1,2)='31' OR SUBSTR(C_PHONE,1,2)='23' OR SUBSTR(C_PHONE,1,2)='29' OR SUBSTR(C_PHONE,1,2)='30' OR SUBSTR(C_PHONE,1,2)='18' OR SUBSTR(C_PHONE,1,2)='17'))
Access_predicates: 
Filter_predicates: (SUBSTR(C_PHONE,1,2)='13'|SUBSTR(C_PHONE,1,2)='31'|SUBSTR(C_PHONE,1,2)='23'|SUBSTR(C_PHONE,1,2)='29'|SUBSTR(C_PHONE,1,2)='30'|SUBSTR(C_PHONE,1,2)='18'|SUBSTR(C_PHONE,1,2)='17')&C_ACCTBAL> (SELECT AVG(C_ACCTBAL) FROM CUSTOMER CUSTOMER WHERE C_ACCTBAL>0.00&(SUBSTR(C_PHONE,1,2)='13'|SUBSTR(C_PHONE,1,2)='31'|SUBSTR(C_PHONE,1,2)='23'|SUBSTR(C_PHONE,1,2)='29'|SUBSTR(C_PHONE,1,2)='30'|SUBSTR(C_PHONE,1,2)='18'|SUBSTR(C_PHONE,1,2)='17'))
Select_level: SEL$8771BF6C
--------------------
Operation: table access
Options: FULL
Object_type: TABLE
Other: 
Object_owner: CALUSER01
Search_columns: 
Projection: O_CUSTKEY
Object_name: ORDERS
Alias: ORDERS@SEL$3
Extended_information: 
Access_predicates: 
Filter_predicates: 
Select_level: SEL$8771BF6C
--------------------
Operation: hash join
Options: ANTI
Object_type: 
Other: 
Object_owner: 
Search_columns: 
Projection:  C_ACCTBAL^C_PHONE
Object_name: 
Alias: 
Extended_information:    AP:O_CUSTKEY=C_CUSTKEY
Access_predicates: O_CUSTKEY=C_CUSTKEY
Filter_predicates: 
Select_level: 
--------------------
Operation: sort
Options: GROUP BY
Object_type: 
Other: 
Object_owner: 
Search_columns: 
Projection:  SUBSTR(C_PHONE,1,2)^SUM(C_ACCTBAL)
Object_name: 
Alias: 
Extended_information: 
Access_predicates: 
Filter_predicates: 
Select_level: SEL$8771BF6C
--------------------
Operation: select statement
Options: 
Object_type: 
Other: 
Object_owner: 
Search_columns: 
Projection: 
Object_name: 
Alias: 
Extended_information: 
Access_predicates: 
Filter_predicates: 
Select_level: 
--------------------