edited by
3,495 views
5 votes
5 votes

The SQL query

SELECT columns
FROM TableA
RIGHT OUTER JOIN TableB
ON A.columnName = B.columnName
WHERE A.columnName IS NULL

returns the following:

  1. All rows in Table $\text{B}$, which meets equality condition above and, none from Table $\text{A}$ which meets the condition.
  2. All rows in Table $\text{A}$, which meets equality condition above and none from Table $\text{B}$, which meets the condition.
  3. All rows in Table $\text{B}$, which meets the equality condition
  4. All rows in Table $\text{A}$, which meets the equality condition
edited by

5 Answers

7 votes
7 votes

None of the above options

Explanation:

SELECT Orders.OrderID, Employees.LastName, Employees.FirstName
FROM Orders
RIGHT JOIN Employees
ON Orders.EmployeeID = Employees.EmployeeID;

This gave the result which is same as option A

but when I executed

SELECT Orders.OrderID, Employees.LastName, Employees.FirstName
FROM Orders
RIGHT JOIN Employees
ON Orders.EmployeeID = Employees.EmployeeID
where Orders.EmployeeID is NULL;

Result had only the records where OrderID was NULL

One can try it on w3schools to get a better understanding.

Also one can refer the following link to get a clear understanding

https://www.dofactory.com/sql/right-outer-join

1 votes
1 votes

Answer (a)

SELECT columns
FROM TableA
RIGHT OUTER JOIN TableB
ON A.columnName = B.columnName
WHERE A.columnName IS NULL

Query returns records of table B which meets equality condition. Thus option (a) matching.

edited by
0 votes
0 votes
option A. all rows from  table B which meets the condition and none from A which MEETS THE CONDITION.
0 votes
0 votes

(1) We are first doing A outer join B in this process all the rows of B which are failed to match with Any row of A(on given col.) are also included in result where All A’s columns are set to NULL

(2) Now we are imposing condition on A by  comparing colName to Null  So we are getting all rows where A.colName = null which are noting but all B table’s row which are failed to match with any row of A 

So this will fetch all rows where B is not matching with any row of A (on given Column)

which does not match with any option

Answer:

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