| # Task: 002 |
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| **Database:** retails |
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| ## Question |
| Count the number of suppliers that offer both air and rail shipping in America. |
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| ## Gold Query |
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|
| ```sql |
| WITH usa_suppliers_with_air AS ( |
| SELECT DISTINCT l.l_suppkey |
| FROM lineitem l |
| JOIN orders o ON l.l_orderkey = o.o_orderkey |
| JOIN customer c ON o.o_custkey = c.c_custkey |
| JOIN nation n ON c.c_nationkey = n.n_nationkey |
| JOIN region r ON n.n_regionkey = r.r_regionkey |
| WHERE r.r_name = 'AMERICA' |
| AND l.l_shipmode = 'AIR' |
| ), |
| usa_suppliers_with_rail AS ( |
| SELECT DISTINCT l.l_suppkey |
| FROM lineitem l |
| JOIN orders o ON l.l_orderkey = o.o_orderkey |
| JOIN customer c ON o.o_custkey = c.c_custkey |
| JOIN nation n ON c.c_nationkey = n.n_nationkey |
| JOIN region r ON n.n_regionkey = r.r_regionkey |
| WHERE r.r_name = 'AMERICA' |
| AND l.l_shipmode = 'RAIL' |
| ) |
| SELECT COUNT(*) AS supplier_count |
| FROM usa_suppliers_with_air a |
| JOIN usa_suppliers_with_rail r ON a.l_suppkey = r.l_suppkey; |
| ``` |
|
|
| **Execution Result:** |
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|
| | supplier_count | |
| |------------------| |
| | 10000 | |
| |
| *1 rows* |
