111. 返回大于等于n的最小整数值? select ceil(n) from dual; 112. 返回小于等于n的最小整数值? select floor(n) from dual; 113. 返回当前月的最后一天? select last_day(sysdate) from dual; 114. 如何不同用户间数据导入? imp system/manager file=aa.dmp fromuser=user_old touser=user_new rows=y indexes=y ;
115. 如何找数据库表的主键字段的名称? sql>select * from user_constraints where constraint_type='p' and table_name='table_name'; 116. 两个结果集互加的函数? sql>select * from bsempms_old intersect select * from bsempms_new; sql>select * from bsempms_old union select * from bsempms_new; sql>select * from bsempms_old union all select * from bsempms_new; 117. 两个结果集互减的函数? sql>select * from bsempms_old minus select * from bsempms_new; 118. 如何配置sequence? 建sequence seq_custid create sequence seq_custid start 1 incrememt by 1; 建表时: create table cust { cust_id smallint not null, ...} insert 时: insert into table cust values( seq_cust.nextval, ...) 119>.日期的各部分的常用的的写法 取时间点的年份的写法:select to_char(sysdate,'yyyy') from dual; 120>.取时间点的月份的写法:select to_char(sysdate,'mm') from dual;
