单项选择题
Which statement is true regarding the INTERSECT operator?（）
A.It ignores NULL values
B.Reversing the order of the intersected tables alters the result
C.The names of columns in all SELECT statements must be identical
D.The number of columns and data types must be identical for all SELECT statements in the query
相关考题
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单项选择题
TheORDERStablebelongstotheuserOE.OEhasgrantedtheSELECTprivilegeontheORDERStabletotheuserHR.WhichstatementwouldcreateasynonymORDsothatHRcanexecutethefollowingquerysuccessfully?（）
A.CREATE SYNONYM ord FOR orders; This command is issued by OE
B.CREATE PUBLIC SYNONYM ord FOR orders; This command is issued by OE
C.CREATE SYNONYM ord FOR oe.orders; This command is issued by the database administrator
D.CREATE PUBLIC SYNONYM ord FOR oe.orders; This command is issued by the database administrator -
多项选择题
Whendoesatransactioncomplete?（）
A.when a DELETE statement is executed
B.when a ROLLBACK command is executed
C.when a PL/SQL anonymous block is executed
D.when a data definition language (DDL) statement is executed
E.when a TRUNCATE statement is executed after the pending transact ion -
单项选择题
WhichstatementistrueregardingtheCOALESCEfunction?（）
A.It can have a maximum of five expressions in a list
B.It returns the highest NOT NULL value in the list for all rows
C.It requires that all expressions in the list must be of the same data type
D.It requires that at least one of the expressions in the list must have a NOT NULL value
