کاملترین منابع و سورس پایگاه داده اوراکل Oracle بیش از 160 صفحه آموزش کامل و جامع اوراکل بیش از 40 صفحه اسلاید ارایه اوراکل بیش از 28 سورس اجرایی اوراکل مراحل آموزش نصب و راه اندازی اوراکل 10 بر روی ویندوز سرور2003 SQL Server: JOIN vs IN vs EXISTS - the logical difference There is a common misconception that IN behaves equaliy to EXISTS or JOIN in terms of returned results.This is simply not true. To see why not, let's review what each statement does.IN:Returns true if a specified value matches any value in a subquery or a list.Exists:Returns true if a subquery contains any rows.Join:Joins 2 resultsets on the joining column. If not read carefully it looks pretty same so far, doesn't it.The difference comes when you take into account the "dreaded" THREE-VALUED LOGIC.Let's ...
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