Home » RDBMS Server » Server Administration » How does EXISTS work?
How does EXISTS work? [message #372874] Thu, 15 March 2001 02:42 Go to next message
Corvax
Messages: 1
Registered: March 2001
Junior Member
Hi, all.
Could somebody tell me how does EXISTS work exactly? I want to know, 'cause I have to determine which of the following queries will work faster:
1.
SELECT 1 FROM dual
WHERE EXISTS (SELECT 1 FROM table where_clause);

2.
SELECT 1 FROM dual
WHERE NOT EXISTS (SELECT 1 FROM table where_clause);

The main idea is to determine if there are some rows in the table or not. And what is the fastest way to do it.

Thanks in advance.

Report message to a moderator

Re: How does EXISTS work? [message #372877 is a reply to message #372874] Thu, 15 March 2001 06:07 Go to previous message
Thirumalai Prakash
Messages: 6
Registered: March 2001
Junior Member
Hi Corvax,

Method 1 is faster than 2.

Report message to a moderator

Previous Topic: ERROR-MESSAGE 20955 / 21408
Next Topic: Could you help me?
Goto Forum:
  

[ Syndicate this forum (XML) ] [ RSS ]

Current Time: Mon Jun 17 02:31:04 CDT 2024
.:: Forum Home :: Blogger Home :: Wiki Home :: Contact :: Privacy ::.