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SubQuery Performace - IN clause or EXISTS clause
In subqueries, which is efficient ,the IN clause or EXISTS clause? Does they produce the same result?
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What is the main difference between the IN and EXISTS clause in subqueries??
The main difference between the IN and EXISTS predicate in subquery is the way in which the query gets executed.IN -- The inner query is executed first and the list of values obtained as its result is used by the outer query.The inner query is executed for only once.EXISTS -- The first row from the outer query is selected ,then the inner query is executed and , the outer query output uses this result...
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