Oracle DQL查询语言整理

 select * from t_hq_ryxx;

 select nianl, xingm from t_hq_ryxx;

 select nianl as 年龄, xingm as 姓名 from t_hq_ryxx t;

 select nianl 年龄 from t_hq_ryxx;

 select nianl || xingm as 年龄和姓名 from t_hq_ryxx;

 select nianl as hhh,t.* from t_hq_ryxx t order by nianl desc ;--排序

 select nianl as hhh,t.* from t_hq_ryxx t order by xingb desc ,bum desc;

 select nianl,xingm,bum,xingb from t_hq_ryxx t order by bum desc nulls last,xingb;

 select * from t_hq_ryxx order by ;

 select nianl,gongz, (nianl+gongz)as g from t_hq_ryxx order by (gongz||nianl);

 --去重复
 select distinct bum from t_hq_ryxx;

 select distinct bum,xingb from t_hq_ryxx;

 select * from t_hq_ryxx;

 select * from t_hq_ryxx where xingb = '1 'and bum = '';

 select * from t_hq_ryxx where (bum = '' or bum = '') and xingb = ''and nianl >'' ;

 select * from t_hq_ryxx where bum is not null;

 --模糊查询 %表示通配符

 select * from t_hq_ryxx where xingm like '三%'

 select * from t_hq_ryxx where xingm like '%儿'

 select * from t_hq_ryxx where xingm like '%三%'

 select * from t_hq_ryxx where gongz <any (select pingjgz from t_hq_bm);

 --值得范围
 select * from t_hq_ryxx where nianl in ('','');

 select * from t_hq_ryxx where nianl ='' or nianl = '';

 --区间范围

 select * from t_hq_ryxx where gongz between  and ;

 select * from t_hq_ryxx where gongz >= and gongz <= ;

 --子查询
 select * from t_hq_ryxx where bum in (select bumbm from t_hq_bm where lianxdh = '');

 --大于最小值，小于最大值

 select * from t_hq_ryxx where gongz >any (select pingjgz from t_hq_bm);

 --大于最大值，小于最小值

 select * from t_hq_ryxx where gongz >all (select pingjgz from t_hq_bm);

 --分组 多种形式
 select bum from t_hq_ryxx group by bum;

 select bum,count() as 数量 from t_hq_ryxx group by bum;

 select bum,count() as 数量,sum (gongz) as 合计 from t_hq_ryxx group by bum;

 select bum,count() as 数量,avg(gongz) as 平均值 from t_hq_ryxx group by bum;

 select nianl, bum,count() as 数量,avg(gongz) as 平均值 from t_hq_ryxx group by nianl, bum;

 select bum,count() as 数量,avg(gongz) as 平均值 from t_hq_ryxx group by bum having avg(gongz)>;