Sergey,

How do I measure query efficiency?

Often, there are multiple ways of writing a single query. For example,
 
SELECT Table1.Field1
FROM   Table1
       INNER JOIN Table2
       ON Table1.PK1 = Table2.FK2
WHERE  Table2.Field2 = value1

could be written,

SELECT Table1.Field1
FROM   Table1
       INNER JOIN
          (SELECT  Table2.Field2, Table2.FK1
           FROM    Table2
           WHERE   Table2.Field2 = value1)
       ON Table1.PK1 = Table2.FK1

or,

SELECT Table1.Field1
FROM   Table1
WHERE  Table1.PK1 IN
          (SELECT  Table2.FK1
           FROM    Table2
           WHERE   Table2.Field2 = value1)

Are any of these more efficient than the others?

The type of query that I am having the most trouble with is when I want to select the rows in a table that don't have their primary keys listed as a foreign key in a table with which it has a 0..* relationship. I have been coding it as,

SELECT Table1.Field1
FROM   Table1
       LEFT OUTER JOIN Table2
       ON Table1.PK1 = Table2.PK2
WHERE  Table2.FK1 IS NULL

Is there a more efficient way to write this query? Microsoft SQL doesn't support MINUS, which would be my first inclination.

Thanks,

>David,
>
>You've no control over how SQL Server utilizes CPU or memory so you should concentrate yor efforts on making the queries as efficient as possible.