基于SQL查询结果的SQL筛选器

Question

Input table - t1

make   | model | engine | kms_covered  | start   | end
-------------------------------------------------------
suzuki | sx4   | petrol | 11           | City A  | City D
suzuki | sx4   | diesel | 150          | City B  | City C
suzuki | swift | petrol | 140          | City C  | City B
suzuki | swift | diesel | 18           | City D  | City A
toyota | prius | petrol | 16           | City E  | City A
toyota | prius | hybrid | 250          | City B  | City E

Need to get a subset of the records such that start and end is only cities where both diesel and hybrid cars were either in start or end .

In above case, expect that only city B qualifies for the condition and expect output table as below

output table

make   | model | engine | kms_covered  | start   | end
-------------------------------------------------------
suzuki | sx4   | diesel | 150          | City B  | City C
suzuki | swift | petrol | 140          | City C  | City B
toyota | prius | hybrid | 250          | City B  | City E

Two step process

1. Get list of cities where both diesel and hybrid cars have either in start or end
2. Subset the table with only records having cities in #1

Need help with starting point as below.

select * from t1
 where start in () or end in ()

Answer 1

Hmmmm . . . If I understand the question, you can get the list of cities using a CTE and then use this in to solve your question:

with c as (
      select city
      from (select start as city, engine
            from t1
            union all
            select end, engine
            from t1
           )
      where engine in ('petrol', 'deisel')
      group by city
      having count(distinct engine) = 2
     )
select t1.*
from t1
where t1.start in (select city from c) and
      t1.end in (select city from c);