047出错的一些题 记录一下
2015-12-23 23:07
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1.which statements are true regarding the usage of the with cluase in complex correlated subqueeires
a.it can be used only with the select cluase
with 必须紧跟sleect使用,这是必须的
2.view the exhibit and examine the data in the employees tables evaluate the following sql statement;
select employee_id,department_id from employees where department_id=50 order by department_id union ...
what would be the outcome of the sql?
d.the statement would not execute because the order by cluase should appear only at the end of the sql statement.
that is ,in the last select statement
放在前面,这条语句就根本不会执行
3.wich two statements are true regarding group by cluase in a sql statement?
a.you can user column in the group by cluase
不可以用别名
4.white three statements are true regarding single-row functions?
a.the can accept only one argument
只是限制输出,并不要求输入为一个参数比如substr
b.they can be nested up to only teo levels
嵌套没有层数限制
c.they can return multiple values of more than one data type
函数只能返回一个值
明天着重搞定执行计划的部分!
a.it can be used only with the select cluase
with 必须紧跟sleect使用,这是必须的
2.view the exhibit and examine the data in the employees tables evaluate the following sql statement;
select employee_id,department_id from employees where department_id=50 order by department_id union ...
what would be the outcome of the sql?
d.the statement would not execute because the order by cluase should appear only at the end of the sql statement.
that is ,in the last select statement
放在前面,这条语句就根本不会执行
3.wich two statements are true regarding group by cluase in a sql statement?
a.you can user column in the group by cluase
不可以用别名
4.white three statements are true regarding single-row functions?
a.the can accept only one argument
只是限制输出,并不要求输入为一个参数比如substr
b.they can be nested up to only teo levels
嵌套没有层数限制
c.they can return multiple values of more than one data type
函数只能返回一个值
明天着重搞定执行计划的部分!
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