query performance - MySQL Embedded SELECTs vs. JOINs -

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क्या इसमें कोई अंतर है: 

  का चयन करें userid, username, userdept, (SELECT Deptname fROM DEFETS WHERE DEPTID = userdept) उपयोगकर्ता नाम से उपयोगकर्ता नाम

और 

  का चयन करें userid, प्रयोक्ता नाम से उपयोगकर्ता INNER depts.deptid = उपयोगकर्ताओं पर शामिल हो जाता है। यूजरडिप

कौन सा बेहतर है?

आपकी दूसरी क्वेरी है बेहतर प्रदर्शन।

आप यह उदाहरण देख सकते हैं:


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