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    <p>I would prefer to use <code>IN</code> in this case as it would be better. However to check the performance you may try to look at the Execution Plan of the query which you are executing. You will get the idea about what performance difference you will get by using the both.</p> <p>Something like this:</p> <pre><code>SELECT id from users where collegeid IN ('1','2','3'....,'1000') </code></pre> <p>According to the <a href="http://dev.mysql.com/doc/refman/5.5/en/comparison-operators.html#function_in" rel="nofollow noreferrer">MYSQL</a> </p> <blockquote> <p>If all values are constants, they are evaluated according to the type of expr and sorted. The search for the item then is done using a binary search. <strong>This means IN is very quick if the IN value list consists entirely of constants.</strong></p> <p>The number of values in the IN list is only limited by the <strong><a href="http://dev.mysql.com/doc/refman/5.1/en/server-system-variables.html#sysvar_max_allowed_packet" rel="nofollow noreferrer">max_allowed_packet</a></strong> value.</p> </blockquote> <p>You may also check <a href="https://stackoverflow.com/questions/3074713/in-vs-or-in-the-sql-where-clause">IN vs OR in the SQL WHERE Clause</a> and <strong><a href="https://stackoverflow.com/questions/782915/mysql-or-vs-in-performance">MYSQL OR vs IN performance</a></strong></p> <p>The answer given by Ergec is very useful:</p> <pre><code>SELECT * FROM item WHERE id = 1 OR id = 2 ... id = 10000 </code></pre> <p>This query took <strong>0.1239 seconds</strong></p> <pre><code>SELECT * FROM item WHERE id IN (1,2,3,...10000) </code></pre> <p>This query took <strong>0.0433 seconds</strong></p> <h1>IN is 3 times faster than OR</h1> <blockquote> <p><strong>will it affect the speed or output in any way?</strong></p> </blockquote> <p>So the answer is <strong>Yes</strong> the performance will be affected.</p>
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    1. PODoes long query string affect the speed?
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    1. USRahul Tripathi
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    1. COThere won't be any performance gain if those columns are indexed..There won't be any significant gain in performance even if they aren't indexed
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      1. USAnirudha
    2. CO@Anirudh: I don't think this claim holds in gneneral. Some DBMS will use an index even if if there is a disjunction / IN sublist in your where clause.
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      1. USFabian
    3. CO@Anirudh - okay, the poster has added the MySQL tag to the question ...
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