131.View the Exhibit and examine the structure of the PRODUCT, COMPONENT, and PDT_COMP tables.
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131.View the Exhibit and examine the structure of the PRODUCT, COMPONENT, and PDT_COMP
tables.
In PRODUCT table, PDTNO is the primary key.
In COMPONENT table, COMPNO is the primary key.
In PDT_COMP table, (PDTNO,COMPNO) is the primary key, PDTNO is the foreign key referencing
PDTNO in PRODUCT table and COMPNO is the foreign key referencing the COMPNO in COMPONENT table.
You want to generate a report listing the product names and their corresponding component names, if the
component names and product names exist.
Evaluate the following query:
SQL>SELECT pdtno,pdtname, compno,compname
FROM product pdt_comp
USING (pdtno) component USING(compno)
WHERE compname IS NOT NULL;
Which combination of joins used in the blanks in the above query gives the correct output?
A.JOIN; JOIN
B.FULL OUTER JOIN; FULL OUTER JOIN
C.RIGHT OUTER JOIN; LEFT OUTER JOIN
D.LEFT OUTER JOIN; RIGHT OUTER JOIN
答案:C
解析:题目要求列出product names和component names,和对应的component names(如果存在的话),从表的定义可以看出
pdt_comp是一个product和component对应关系表,并且他的主键对应的分别对应两个表的字段,
因此这里A和C其实结果是一样的(因为是外键的关系,并且这里也说明了不存在null的情况,if the
component names and product names exist.),所以我觉得AC都正确
tables.
In PRODUCT table, PDTNO is the primary key.
In COMPONENT table, COMPNO is the primary key.
In PDT_COMP table, (PDTNO,COMPNO) is the primary key, PDTNO is the foreign key referencing
PDTNO in PRODUCT table and COMPNO is the foreign key referencing the COMPNO in COMPONENT table.
You want to generate a report listing the product names and their corresponding component names, if the
component names and product names exist.
Evaluate the following query:
SQL>SELECT pdtno,pdtname, compno,compname
FROM product pdt_comp
USING (pdtno) component USING(compno)
WHERE compname IS NOT NULL;
Which combination of joins used in the blanks in the above query gives the correct output?
A.JOIN; JOIN
B.FULL OUTER JOIN; FULL OUTER JOIN
C.RIGHT OUTER JOIN; LEFT OUTER JOIN
D.LEFT OUTER JOIN; RIGHT OUTER JOIN
答案:C
解析:题目要求列出product names和component names,和对应的component names(如果存在的话),从表的定义可以看出
pdt_comp是一个product和component对应关系表,并且他的主键对应的分别对应两个表的字段,
因此这里A和C其实结果是一样的(因为是外键的关系,并且这里也说明了不存在null的情况,if the
component names and product names exist.),所以我觉得AC都正确
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