下面的SQL哪些有可能经过两个阶段（只经过一次shuffle）就计算出结果：（ ） A: SELECT key1, key2, SUM(value1) FROM (SELECT key1, key2, COUNT(*) FROM dual GROUP BY key1, key2) t1 GROUP BY key2, key1; B: SELECT a.key1, a.key2 FROM table1 a JOIN table2 b ON a.key1 = b.key; C: SELECT *, ROW_NUMBER() OVER(PARTITION BY key ORDER BY value1, value 2) id1, ROW_NUMBER() OVER(PARTITION BY key ORDER BY value1) id2 FROM dual;

HashMap中的put()方法参数是() A: put(value,key) B: put(key,key) C: put(key,value) D: put(key,key)

According to the main area of pixels in the histogram, the tone can be divided into A: Low key, high key, middle key B: Hard tone, soft tone C: Long key, short key D: Long key, middle key, short key

关键码key实际存放的位置是： A: key B: key - 1 C: hash(key) D: hash(hash(key))

下列表达正确的是（ ）。 A: if（key=0）‍ B: if（key==0） C: for(key=0) D: while(key=0);

在JSON字符串中，Object结构是（ ）。 A: key , value B: {key:value,key:value...} C: Key D: value

The principle of uniformitarianism indicates that ______. A: the past is the "key" to the future B: tomorrow is the "key" to the past C: the present is the "key" to the past D: the past is the "key" to the present

判断键盘中A键是否被按下的正确语句是（ ） A: key='A'； B: key="A"； C: key=='A'； D: key=="A"；

The mark of a common flat key is: KEY 12x80 GB 1096-2003, the type of this key is ( ) A: Round head common flat key B: Square head common key C: Half round head common flat key D: Other flat keys

2. 以下哪个关键字可以定义外键约束。（） A: Primary Key B: Unique key C: Default Key D: Foreign Key