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The database is entirely free to evaluate lazily or eagerly. In fact, it can evaluate thrice in reverse order for all I know :) In your example, I would expect SQL Server to choose the best way without any hints or tricks.
SQL Server Table Spool Operator (Lazy Spool) Te SQL Server Lazy Spool is used to build a temporary table on the TempDB and fill it in lazy manner. In other words, it fills the table by reading and storing the data only when individual rows are required by the parent operator.
Seek Predicate is the seek operation that uses the b-tree part of the index to find matching rows. Predicate is an operation that after the Seek Predicate operation does additional filterin using non-key columns (and sometimes also on indexed columns).
A predicate is an expression that evaluates to TRUE, FALSE, or UNKNOWN. Predicates are used in the search condition of WHERE clauses and HAVING clauses, the join conditions of FROM clauses, and other constructs where a Boolean value is required.
I have a query:
SELECT
someFields
FROM
someTable
WHERE
cheapLookup=1
AND (CAST(someField as FLOAT)/otherField)<0.9
So, will the CAST and division be performed in the case that cheapLookup is 0? If not, how can I avoid the calculation in this case?
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