Which statement is true regarding the UNION operator?
A.
By default, the output is not sorted
B.
NULL values are not ignored during duplicate checking
C.
Names of all columns must be identical across all SELECT statements
D.
The number of columns selected in all SELECT statements need to be the same
B Wrong
Kindly check the right one
http://www.aiotestking.com/oracle/which-statement-is-true-regarding-the-union-operator-3/
A is ok, B is wrong
sorry not A, but the last one is ok – D.
Materace do Spania
http://www.dYNihcArR6.com/dYNihcArR6
Again another question here that has the incorrect answer.
Try this:
1 select 2, 2 from dual
2 union
3* select 1 from dual
sql> /
select 2, 2 from dual
*
ERROR at line 1:
ORA-01789: query block has incorrect number of result columns
So D is the only correct answer.
Far too many questions in this exam are giving incorrect answers. Makes this test exam practially pointless.
Who did the quality control on this? Tell them to go an do SQL Server.
B and D is correct here.