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count与count(*)的区别是()。
- A、无区别
- B、count是聚合函数,count(*)不是聚合函数
- C、count统计空格而COUNT(×)不统计
- D、count(*)统计NULL值,而COUNT不统计
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更多 “count与count(*)的区别是()。A、无区别B、count是聚合函数,count(*)不是聚合函数C、count统计空格而COUNT(×)不统计D、count(*)统计NULL值,而COUNT不统计” 相关考题
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考题
单选题count与count(*)的区别是()。A
无区别B
count是聚合函数,count(*)不是聚合函数C
count统计空格而COUNT(×)不统计D
count(*)统计NULL值,而COUNT不统计
考题
单选题编译如下Java程序片断: class test{ int count = 9; public void a(){ int count=10; System.out.println("count 1 =" + count); } public void count(){ System.out.println("count 2 =" + count); } public static void main(String args[]){ test t=new test(); t.a(); t.count(); } } 结果将()。A
不能通过编译B
输出: count 1 = 10 count 2 = 9C
输出:count 1 = 9 count 2 = 9
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单选题编译如下的Java程序片段: Class test{ Int count=9; Public void a(){ Int count=10; System.out,println(“count 1=” + count); } Public void count(){ System.out.println(“count 2 =”+ count); } Public static void main(String args[] ){ Test t=new Test(); t.a(); t.count(); } } 结果是()A
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输出:count 1=9 count 2=9
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