Select A.XX,B.XXX,C.XXX
From A
INNER JION B ON A.aID=B.aID
Right outer Join C ON A.aID=C.aID
这语句接合顺序是?先内连接还是先外连接?
还是按语句的出现顺序去执行?
From A
INNER JION B ON A.aID=B.aID
Right outer Join C ON A.aID=C.aID
这语句接合顺序是?先内连接还是先外连接?
还是按语句的出现顺序去执行?
From A
INNER JION B ON A.aID=B.aID --1.
Right outer Join C ON A.aID=C.aID --2.
Select A.XX,B.XXX,C.XXX
From A
INNER JION B ON A.aID=B.aID
Right outer Join C ON A.aID=C.aID
按语句的顺序来!
---
1. 先where 后select
2. 先where 再group 再having 后select
3. 先where 再group 再having 再select 后order
4. 先join 再where 后select Select A.XX,B.XXX,C.XXX
From A
INNER JION B ON A.aID=B.aID --1
Right outer Join C ON A.aID=C.aID--2