select A from B where C=‘D’and E=‘F’ 如果 F=null 则把E='F' 换成 M='N'select A from B where C=‘D’and M=‘N’ 求写成一个select语句 用的是DB2数据库 C和E都是主keyselect A from B where C=‘D’and E=nvl(‘F’,E) and

select * from a union select * from b 能详细说下么 select * into b from a where 11 insert into a select * from b 和select * into a from b 这两个语句是不是一样的? select c.*,d* from ( select 图号 from ( SELECT a.*,b.存货编码 FROM 未明图号 as a left OUTER JOIN 存select c.*,d* from ( select 图号 from (SELECT a.*,b.存货编码FROM 未明图号 as a left OUTER JOIN 存货档案 as bON a.图号=b.规 Someone may hide behind the door ,___he could hear what we talked about clealy.A.where B.from wher HQL 的语法：select a from a where a=3 or select b from b whereb=2 要怎么写? SQL2005 报错 在关键字'group' 附近有语法错误select a,b,sum(x) from (select a,b,'1' as x from aaaunion allselect a,b,'-1' as x from bbb)group by a,b改成下面这样还是同样报错：select a,b,sum(x) from (select a,b,'1' as x from aaa select * from a,b与select * from a inner join b 的取数方式和执行效率有什么不同, select a,b from 表名 group by a,b order by count(*) desc select * from table_a a,table_b b where a.col1 = b.col1(+) ;最后的(+)怎么解释? 帮我看看这个oracle语句,select groupid,parentid,groupname,isleaf,description,sharerankid,statusid,corporationid,staffid,isactual,groupcount,level FROM (SELECT a.*,b.groupcount FROM teabgroup a,(SELECT groupid,count(*) groupcount FROM teabmembe oracle exists函数用法select A.DEPTNO,A.NAME FROM A WHERE EXISTS (SELECT 1 FROM B WHERE A.DEPTNO=B.DEPTNO)中的SELECT 不会是查找是1的值吧? oracle查询语句 select a||','||b||','||c from table where a in('m','n') select ** from A where A.id in (select id from B where ****) 在以下哪种情况,select ** from A whereselect ** from A where A.id in (select id from B where ****) 在以下哪种情况,此语句执行的速度快：（1）A表的记录数远多于 SQL语句理解 select * from B where (select count(1) as num from A where A.ID = B.ID) = 0select * from B where (select count(1) as num from A where A.ID = B.ID) = 0请问如何理解,为什么 可以在B表中 排除A表的数据 解释数SQL面的 select * from a, b 是什么意思如题 sql语句 后面的(+) select * from t1,t2 where t1.a=t2.b(+) 一个SQL语言,关于ANY 和ALL Q1:SELECT a FROM R WHERE b>= ANY (SELECT d FROM S WHERE c>10);Q2:SELECT a FROM R WHERE b>= ALL(SELECT d FROM S WHERE c>10);(A) Q1和Q2产生的结果一样; (B) Q1的结果总是包含Q2的结果;(C) Q2的结果总是