98.Which statement is true regarding the COALESCE function?
2016-03-04 15:59
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98.Which statement is true regarding the COALESCE function?
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.
答案：C
解析：
COALESCE：返回第一个不为null的值，必须至少两个表达式，如果表达式全为null，那么返回null，参数类型必须相等
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.
答案：C
解析：
COALESCE：返回第一个不为null的值，必须至少两个表达式，如果表达式全为null，那么返回null，参数类型必须相等
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