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单选题
Consider this syntax： MERGE INTO t1 USING t2 ON （join predicate）….. What does the MERGE syntax do？（）
A
It performs a merge join of the row from T2 only if it doesn’t exist in the T1 table.
B
It creates a natural join of tables T1 and T2 for all columns that have the same name.
C
It creates a Cartesian product of table T1 and table T2 for all columns that have the same name.
D
For each row from T2, it updates the row if it exists within table T1, otherwise it inserts the row into T1.
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更多 “单选题Consider this syntax： MERGE INTO t1 USING t2 ON （join predicate）….. What does the MERGE syntax do？（）A It performs a merge join of the row from T2 only if it doesn’t exist in the T1 table. B It creates a natural join of tables T1 and T2 for all columns that have the same name. C It creates a Cartesian product of table T1 and table T2 for all columns that have the same name. D For each row from T2, it updates the row if it exists within table T1, otherwise it inserts the row into T1.” 相关考题
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