Compare performance difference of T-SQL Between and '<' '>' operator?

后端 未结 7 1179
情歌与酒
情歌与酒 2020-12-31 05:02

I\'ve tried searching through search engines,MSDN,etc. but can\'t anything. Sorry if this has been asked before. Is there any performance difference between using the T-SQL

7条回答
  •  有刺的猬
    2020-12-31 05:38

    Love when folks give code to do your own testing, you need to do a larger subset / repeated test to account for indexes being loaded into memory, etc... before jumping to conclusions though. Here is the same code with a larger table and 10 iterations

    DECLARE
        @Startdatetime datetime ,
        @Diff int = 0 ,
        @Addrowcount int = 1000 ,
        @ptr int = 1;
    
    
    SET NOCOUNT ON;
    
    --Create a tempory table to perform our tests on
    DROP TABLE dbo.perftest
    
    CREATE TABLE dbo.perftest( id int NOT NULL
                                           IDENTITY(1 , 1)
                                           PRIMARY KEY ,
                               mytext nvarchar( 50 )NOT NULL );
    
    --Now add some sample rows
    
    SET @Addrowcount = 20000;
    
    WHILE(@Addrowcount > 0)
    
        BEGIN
    
            INSERT INTO dbo.perftest( mytext )
            VALUES( 'thetext' );
    
            SET @Addrowcount = @Addrowcount - 1;
    
        END;
    
    WHILE @ptr < 10 -- do this a few times to account for indexes being loaded into memory
    
    BEGIN
    
        SELECT @Startdatetime = GETDATE();
    
        -- do method 1 here
    
        SELECT mytext
          FROM dbo.perftest
          WHERE(id >= (100 + (@ptr * 1000)))
           AND (id <= (500 + (@ptr * 1000)));
    
        --end method1
    
        SELECT @Diff = DATEDIFF( millisecond , @Startdatetime , GETDATE());
    
        PRINT ':Method 1: ' + CAST(@Diff AS nvarchar( 20 )) + ' ms';
    
        --reset start time
    
        SELECT @Startdatetime = GETDATE();
    
        --do method2 here
    
        SELECT mytext
          FROM dbo.perftest
          WHERE id BETWEEN (300 + (@ptr * 1000))
            AND (800 + (@ptr * 1000));
    
        --end method2
    
        SELECT @Diff = DATEDIFF( millisecond , @Startdatetime , GETDATE());
    
        PRINT ':Method 2: ' + CAST(@Diff AS nvarchar( 20 )) + ' ms';
    
        SET @ptr = @ptr + 1
    
    END
    

    Gives you a very different set of results:

    --Method 1    -- 10 ms
    --Method 2    -- 33 ms
    --Method 1    -- 40 ms
    --Method 2    -- 26 ms
    --Method 1    -- 23 ms
    --Method 2    -- 23 ms
    --Method 1    -- 13 ms
    --Method 2    -- 16 ms
    --Method 1    -- 13 ms
    --Method 2    -- 20 ms
    --Method 1    -- 6 ms
    --Method 2    -- 16 ms
    --Method 1    -- 26 ms
    --Method 2    -- 16 ms
    --Method 1    -- 13 ms
    --Method 2    -- 13 ms
    --Method 1    -- 16 ms
    --Method 2    -- 13 ms
    

    I would say from this (still pretty unscientific) test, not much difference either way.

提交回复
热议问题