weixin_38919176的博客

1、plsql查询服务器上Oracle使用的字符集select * from v$nls_parameters where parameter like 'NLS_CH%';2、设置环境变量(我的电脑–>属性–>更改设置–>高级–>环境变量–>新建)

1、join 内关联SELECT A1.Region_Name REGION, SUM(A2.Sales) SALESFROM Geography A1, Store_Information A2WHERE A1.Store_Name = A2.Store_NameGROUP BY A1.Region_Name;2、outer join 外关联left out join 等价于 left joinright out join 等价于 right join在 O.

查询格式如下：select 字段名 from 表名 start with 子节点字段名='指定值' connect by prior 子节点字段名=父节点字段名或者select 字段名 from 表名 start with 子节点字段名='指定值' connect by prior 父节点字段名=子节点字段名备注：parentcode 父节点字段名guid 子节点字段名1、从孩子结点>>父节点>>根节点select t.* from ba_marketcod

APPROVEDATE 为date类型根据指定时间进行数据查询正确写法如下：select tb.APPROVEDATE from test t where to_char(tb.APPROVEDATE, 'yyyy/MM') = to_char(to_date('202011', 'yyyy/MM'), 'yyyy/MM')

select 字段列表,TB.SELLERNAME from 表名 TB ORDER BY NLSSORT(TB.SELLERNAME, 'NLS_SORT=SCHINESE_PINYIN_M')1、按拼音排序NLS_SORT = SCHINESE_PINYIN_M2、按笔画排序NLS_SORT = SCHINESE_STROKE_M3、按部首排序NLS_SORT = SCHINESE_RADICAL_M...

1、左关联(左表全部数据、右表满足关联条件数据)select a.age aage, a.tag atag, b.age bage, b.tag btag from a a, a1 b where a.age = b.age(+); 等价于：select a.age aage, a.tag atag, b.age bage, b.tag btag from a a left join a1 b on a.age = b.age结果：2、右关联（右表全部数据、左表满足关联条件数

alter table a alter column eventtype varchar2(50);错误原因-解决办法：alter table a modify eventtype varchar2(50);修改字段类型：原来：eventtype number(10)alter table a modify eventtype varchar2(50);修改字段名：alter table a rename column eventtype to eventtypessss...