Question

Is there a faster way to write the following query on a table called OrderDtl?

OrderId Product
1       ORANGE
1       APPLE
2       SHAMPOO
2       SOAP
2       TOOTHPASTE

---

SELECT *
FROM OrderDtl
WHERE OrderId in
    (
        SELECT OrderId
        FROM OrderDtl
        WHERE Product='APPLE'
    )

---

Which results in

1       ORANGE
1       APPLE

Answer 1

Join the table to itself.

After seeing the comment from Dems I changed the SQL to add a couple of indexes:

CREATE TABLE #OrderDtl (OrderId INT, Product CHAR(10))

CREATE CLUSTERED INDEX IX_Order ON #OrderDtl (OrderId) 
CREATE NONCLUSTERED INDEX IX_Order_Product ON #OrderDtl (Product) INCLUDE (OrderId)

INSERT #OrderDtl SELECT 1, 'ORANGE'
INSERT #OrderDtl SELECT 1, 'APPLE'
INSERT #OrderDtl SELECT 2, 'SHAMPOO'
INSERT #OrderDtl SELECT 2, 'SOAP'
INSERT #OrderDtl SELECT 2, 'TOOTHPASTE'

SELECT T2.* 
FROM #OrderDtl T1 INNER JOIN #OrderDtl T2
ON T1.OrderId = T2.OrderId
WHERE T1.Product='APPLE'

SELECT *
FROM #OrderDtl
WHERE OrderId in
    (
        SELECT OrderId
        FROM #OrderDtl
        WHERE Product='APPLE'
    )

Comparing the resulting execution plans is interesting, for this trivial example the result is the same:

EDIT:
Adding the execution plan of esastincy answer, it’s the same again in execution “effort”

You may also be interested in this article: SQL Server: JOIN vs IN vs EXISTS – the logical difference