* Chuck Gadd
> Roger Baklund wrote:
>
> >>Either way, I was surprised to see the "like" to be in the top
> >>performers and "left()" to be last.
> >
> > I suppose the LIKE operator is optimized for the case when it
> > begins with a constant:
> >
> > mysql> select BENCHMARK(1000, 'dfsfsdfs' lik
Roger Baklund wrote:
Either way, I was surprised to see the "like" to be in the top
performers and "left()" to be last.
I suppose the LIKE operator is optimized for the case when it begins with a
constant:
mysql> select BENCHMARK(1000, 'dfsfsdfs' like '%F%' );
1 row in set (3.43 sec)
MySql w
* ed aka emierzwa at micron.com
> I'm on WinXP, 2.6ghz. mysqld-nt Alpha 4.1.2
w2k, 0.6ghz, 3.23.30-gamma
> Either way, I was surprised to see the "like" to be in the top
> performers and "left()" to be last.
I suppose the LIKE operator is optimized for the case when it begins with a
constant:
I'm on WinXP, 2.6ghz. mysqld-nt Alpha 4.1.2
Either way, I was surprised to see the "like" to be in the top
performers and "left()" to be last.
Ed
---
* ed aka emierzwa at micron.com
> You could just use the benchmark function?
>
> select BENCHMARK(1000, 'dfsfsdfs' li
* ed aka emierzwa at micron.com
> You could just use the benchmark function?
>
> select BENCHMARK(1000, 'dfsfsdfs' like 'F%' ) /* 0.45 sec. */
> select BENCHMARK(1000, 'dfsfsdfs' between 'F' and 'Fzzz' ) /* 0.55
> sec. */
> select BENCHMARK(1000, left('dfsfsdfs',1)='F' ) /* 0.79 sec.
7;,1)='F' ) /* 0.79 sec. */
The times go up a little if the strings are a match.
Ed
-Original Message-
From: Roger Baklund [mailto:[EMAIL PROTECTED]
Sent: Wednesday, January 21, 2004 1:11 PM
To: [EMAIL PROTECTED]
Cc: Hassan Shaikh
Subject: Re: Efficient SQL Statement
* Hassan Shaikh
* Hassan Shaikh
> Which one of the following statements is more efficient?
>
> SELECT * FROM COUNTRY WHERE LEFT(CNNAME,1)='B';
>
> Or
>
> SELECT * FROM COUNTRY WHERE CNNAME LIKE 'B%';
The second statement will normally be the most effective, because the server
don't need to perform a function on t
Hi All,
Which one of the following statements is more efficient?
SELECT * FROM COUNTRY WHERE LEFT(CNNAME,1)='B';
Or
SELECT * FROM COUNTRY WHERE CNNAME LIKE 'B%';
Thanks.
Hassan
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