The person who writes the program often needs to analyze whether the SQL statement that has been written has been optimized, and how fast the server responds, this time it needs to use the statistics state value of SQL to view it.
by setting Statistics we can view the system situation when executing SQL. The options are Profile,io, time. Introduced as follows:
SET STATISTICS profile on: Displays the time, in milliseconds, that is required to parse, compile, and execute the query.
SET STATISTICS IO on: Reports information about the number of scans per table referenced in the statement, the number of logical reads (pages accessed in the cache), and the number of physical reads (the number of times the disk was accessed).
Set STATISTICS time on: Displays the result set after each query execution, representing the configuration file that the query executes.
How to use: Open SQL SERVER Query Analyzer and enter the following statement:
SET STATISTICS profile on
SET STATISTICS IO on
SET STATISTICS time on
Go/*--your SQL script to start */
SELECT [TestCase] from [Testcaseselect]
GO/*--the end of your SQL script */
SET STATISTICS Profile OFF
SET STATISTICS IO OFF
SET STATISTICS Time OFF
Effect:
Alternatively, you can determine how efficient the SQL statement is by adding statements manually to calculate the execution time to see how much time is spent executing the statement:
DECLARE @d datetime
Set @d=getdate ()
/* Your SQL script starts */
SELECT [TestCase] from [Testcaseselect]
/* End of your SQL script */
Select [Statement execution takes time (milliseconds)]=datediff (Ms,@d,getdate ())
View SQL statement execution time/test SQL statement Performance