SET STATISTICS IO, TIME ON
SET SHOWPLAN ON

-- Report all Products with Current State of 3
-- Subquery

SELECT  p.ProductId,
        p.Description, 
        ps.DateTime 
    FROM  Product       p,
          ProductStatus ps
    WHERE p.ProductId = ps.ProductId  -- Join
    AND   StatusCode  = 3             -- Request
    AND   DateTime    = (             -- Current Status on the left ...
        SELECT MAX( DateTime )        -- Current Status row for outer Product
            FROM  ProductStatus subquery
            WHERE subquery.ProductId = ps.ProductId
            )

----------------
-- Query Plan --
----------------

QUERY PLAN FOR STATEMENT 3 (at line 7).


    STEP 1
        The type of query is SELECT.

	6 operator(s) under root

       |ROOT:EMIT Operator (VA = 6)
       |
       |   |NESTED LOOP JOIN Operator (VA = 5) (Join Type: Inner Join)
       |   |
       |   |   |SQFILTER Operator (VA = 3) has 2 children.
       |   |   |
       |   |   |   |SCAN Operator (VA = 0)
       |   |   |   |  FROM TABLE
       |   |   |   |  Product
       |   |   |   |  p
       |   |   |   |  Table Scan.
       |   |   |   |  Forward Scan.
       |   |   |   |  Positioning at start of table.
       |   |   |   |  Using I/O Size 8 Kbytes for data pages.
       |   |   |   |  With LRU Buffer Replacement Strategy for data pages.
       |   |   |
       |   |   |  Run subquery 1 (at nesting level 1).
       |   |   |
       |   |   |  QUERY PLAN FOR SUBQUERY 1 (at nesting level 1 and at line 16).
       |   |   |
       |   |   |   Correlated Subquery.
       |   |   |   Subquery under an EXPRESSION predicate.
       |   |   |
       |   |   |   |SCALAR AGGREGATE Operator (VA = 2)
       |   |   |   |  Evaluate Ungrouped MAXIMUM AGGREGATE.
       |   |   |   |
       |   |   |   |   |SCAN Operator (VA = 1)
       |   |   |   |   |  FROM TABLE
       |   |   |   |   |  ProductStatus
       |   |   |   |   |  subquery
       |   |   |   |   |  Using Clustered Index.
       |   |   |   |   |  Index : UC_Prod_Dtm
       |   |   |   |   |  Forward Scan.
       |   |   |   |   |  Positioning by key.
       |   |   |   |   |  Keys are:
       |   |   |   |   |    ProductId ASC
       |   |   |   |   |  Using I/O Size 2 Kbytes for data pages.
       |   |   |   |   |  With LRU Buffer Replacement Strategy for data pages.
       |   |   |
       |   |   |  END OF QUERY PLAN FOR SUBQUERY 1.
       |   |
       |   |   |SCAN Operator (VA = 4)
       |   |   |  FROM TABLE
       |   |   |  ProductStatus
       |   |   |  ps
       |   |   |  Using Clustered Index.
       |   |   |  Index : UC_Prod_Dtm
       |   |   |  Forward Scan.
       |   |   |  Positioning by key.
       |   |   |  Keys are:
       |   |   |    ProductId ASC
       |   |   |    DateTime ASC
       |   |   |  Using I/O Size 2 Kbytes for data pages.
       |   |   |  With LRU Buffer Replacement Strategy for data pages.


---------------------
-- Execution Stats --
---------------------

Parse and Compile Time 0.
Adaptive Server cpu time: 0 ms.
Total writes for this command: 0
 
Execution Time 0.
Adaptive Server cpu time: 0 ms.  Adaptive Server elapsed time: 0 ms.
Total writes for this command: 0
 
Execution Time 0.
Adaptive Server cpu time: 0 ms.  Adaptive Server elapsed time: 0 ms.
Table: Product       (p)        scan count 1,     logical reads: (regular=2000  apf=0 total=2000),  physical reads: (regular=0 apf=0 total=0), apf IOs used=0
Table: ProductStatus (subquery) scan count 20000, logical reads: (regular=97287 apf=0 total=97287), physical reads: (regular=0 apf=0 total=0), apf IOs used=0
Table: ProductStatus (ps)       scan count 20000, logical reads: (regular=80000 apf=0 total=80000), physical reads: (regular=0 apf=0 total=0), apf IOs used=0
Total writes for this command: 0
 
Execution Time 17.
Adaptive Server cpu time: 1700 ms.  Adaptive Server elapsed time: 1843 ms.
Total writes for this command: 0
 
Execution Time 0.
Adaptive Server cpu time: 0 ms.  Adaptive Server elapsed time: 0 ms.