1 SQL语句中怎么去掉字段内容右边的空格？ SQL SERVER中的是RTRIM（ ），ORACLE中呢？
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用法差不多：
SQL> select ltrim(' dfs'),rtrim('dfsdf '),trim(' df df '),ltrim('1112121','1') from dual;

LTRIM('DFS') RTRIM('DFSDF') TRIM('DFDF') LTRIM('1112121','1')
------------ -------------- ------------ --------------------
dfs dfsdf df df 2121

2 SQL SERVER中截取字段内容内容,例如SUBSTRING( fieldname, 1, 2)，ORACLE中怎么做？
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用法一样，函数名是substr( fieldname, 1, 2)

3 SQL SERVER中比较日期 select * from table where fieldname>'2005-01-01' ,ORACLE中这样写不行，该怎么写呢？

fieldname是date类型的话，select * from table where fieldname> date '2005-01-01'或者
select * from table where fieldname>to_date('2005-01-01','yyyy-mm-dd')







declare @a varchar(8000)
set @a='aaaa bbb'
select left(@a,charindex(' ',@a)-1)
---测试----
aaaa





declare
i integer:=1;
j integer:=1;
k integer:=1;
cursor c1 is
select t.id,replace(t.name,' ')as realname from bjpuserinfo t where t.name like '% %' and t.accounttype='qiye';
begin
for rec in c1 loop
update bjpuserinfo set name=rec.realname where id=rec.id;
update awardarchive set qiyename=rec.realname where qiyeid=rec.id;
update qiyeinfo set unitname=rec.realname where id=rec.id;
end loop;
end;