LEFT JOIN用于

A . A.JOINONTOFOR[FIELDS] B . B.JOINWITHONFOR[FIELDS] C . C.JOINONWITHFOR[FIELDS] D . D.JOINWITHTOFOR[FIELDS]

A . 可将相似的对象合并为一个对象 B . 合并两条或多条圆弧时，将从源对象开始沿顺时针方向合并圆弧 C . 还可以合并样条曲线和多段线 D . 也可以使用圆弧和椭圆弧创建完整的圆和椭圆

A . The tables being joined have NOT NULL columns. B . The tables being joined have only matched data. C . The columns being joined have NULL values. D . The tables being joined have only unmatched data. E . The tables being joined have both matched and unmatched data. F . Only when the tables have a primary key/foreign key relationship.

A . Both tables have NULL values. B . You want all unmatched data from one table. C . You want all matched data from both tables. D . You want all unmatched data from both tables. E . One of the tables has more data than the other. F . You want all matched and unmatched data from only one table.

A . 从源对象逆时针合并圆弧 B . 从源对象顺时针合并圆弧 C . 从目标对象逆时针合并圆弧 D . 从目标对象顺时针合并圆弧

A . INNERJOIN B . LEFTJOIN C . RIGHTJOIN D . FULLJOIN

A . OK! I'm coming B . No, you do the same C . Oh, that's all right D . Don't mention it

A . 两个数据表都不能打开 B . 两个数据表都必须打开 C . 一个表打开，一个表关闭 D . 两个数据表必须结构相同

A.comrade-in-arms B.comrades-in-arms C.comrades-in-arm D.comrade-in-arm

是 否

是 否

A．helloworl选项D)! B．helloworld!&39; C．helloworld D．listhelloworld!)

A.Because she doesn’t drink coffee. B.Because she has a plane to catch. C.Because she has to go to a lesson. D.Because she doesn’t like the man.

A．A.hello world ! B．B.’hello world!’ C．C.hello world D．D.list(‘hello world!’)

A．don't B．won't C．didn't

A．有非等值连接 B．连接的关联条件 C．关联条件需为等值连接 D．多个条件之间需用and连接

A．两个数据库都不能打开 B．两个数据库必须在不同工作区打开 C．一个数据库在当前工作区打开 D．两个数据库的结构必须相同

A．包括table_2中的所有行,不包括table_1的不匹配行 B．包括table_1中的所有行,不包括table_2的不匹配行 C．包括两个表的所有行 D．只包括table_1和table_2满足条件的行

A．LEFT OUTER JOIN B．RIGHT OUTER JOIN C．INNER JOIN D．FULL OUTER JOIN 此题为多项选择题。