根据SQL:select a.a,a.b,a.c,b.c,b.d,b.f from a LEFT OUT JOIN b ON a.a = b.c写出右外连接

sql里,where a in (select .) and b in (select .)这种表示合法吗? 根据SQL:select a.a,a.b,a.c,b.c,b.d,b.f from a LEFT OUT JOIN b ON a.a = b.c写出右外连接 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(+) 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 select * from a union select * from b 能详细说下么 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 sql函数,select count(A.abc) as sum from A left join B on A.id=B.id where A.abc='1' group by A.abc结果是 sum 234怎么求count(A.abc) as sum 的总数. if we want to retrieve data from the database with SQL,we should use the comand of ( )A、select B、update C、delete D、insert SQL是______英文单词的缩写（1分A、Standard Query Languange B、Structured Query Language C、Select Query Language D、以上都不是 sql语句and 1=1是什么意思?select a.ename, a.mgr, a.sal, b.deptnofrom emp a, dept bwhere a.deptno = b.deptnoand b.deptno in ('ACCOUNTING', 'RESEARCH', 'SALES', 'OPERATIONS')AND 1=1; SQL语句SELECT*FORM TABLE-A WHERE name LIKE‘-mation‘ 的功能?还有SELECT*FORM TABLE-A WHERE name LIKE‘%mation‘ 的功能. select * into b from a where 11 关于SQL语句里面的A.XX,和B.select B.kecheng,B.score,B.xuehaofrom(select kecheng ,max(score) AS score from jiaScore group by kecheng) A,jiaScore Bwhere A.kecheng = B.kechengand A.score = B.score例如我这段数据库语句,A.kecheng和B.keche select a versino,piease! Select a username是什么意思 to select a Select a country是什么意思