Below is an example ofSELECT a.EmployeeIDFROM HumanResources.Employee aWHERE a.ContactID IN(SELECT b.ContactIDFROM Person.Contact bWHERE b.Title = 'Mrs.')Select one:a.Noncorrelated Subqueryb.Correlated SubqueryClear my choice
Question
Below is an example ofSELECT a.EmployeeIDFROM HumanResources.Employee aWHERE a.ContactID IN(SELECT b.ContactIDFROM Person.Contact bWHERE b.Title = 'Mrs.')Select one:a.Noncorrelated Subqueryb.Correlated SubqueryClear my choice
Solution
The given SQL query is an example of a Noncorrelated Subquery.
In a noncorrelated subquery, the inner SELECT query runs first and passes its results to the outer query. The outer query uses this result to complete its execution. In this case, the inner query is selecting ContactID from Person.Contact where the title is 'Mrs.' The result of this query is then used by the outer query to select EmployeeID from HumanResources.Employee where the ContactID matches those returned by the inner query.
In contrast, a correlated subquery is a subquery that uses values from the outer query. In this case, the inner query would depend on the outer query for its values, which is not what is happening in the provided SQL statement.
Similar Questions
Which of the following is a correlated subquery?Select one:a.Uses the result of an outer query to determine the processing of an outer queryb.Uses the result of an inner query to determine the processing of an outer queryc.Uses the result of an inner query to determine the processing of an inner queryd.Uses the result of an outer query to determine the processing of an inner query
Often, a correlated subquery looks like a nested loop join. Select one:TrueFalse
What is a correlated sub-query?Select one:a.A sub-query that substitutes the names of the outer queryb.A sub-query that uses the correlation name of an outer queryc.A sub-query that does not depend on its outer query’s correlation namesd.An independent query that uses the correlation name of another independent query.
Which one is not a type of subquery ?
Select the correct answerWhich one is not a type of subquery ?OptionsMultiple row sub querySingle row sub queryCorrelated Sub queryVariation based Sub query
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