常用的　sql

SELECT * FROM student JOIN score

SELECT * FROM student stu JOIN score sco

SELECT * FROM student stu JOIN score sco on stu.`ROW_ID` = sco.`SID`

SELECT * FROM student stu LEFT JOIN score sco ON stu.`ROW_ID` = sco.`SID`

SELECT stu.`ROW_ID`,stu.`SNAME`,sco.`C_SCORE` FROM student stu LEFT JOIN score sco ON stu.`ROW_ID` = sco.`SID` WHERE stu.`ROW_ID` =1

SELECT stu.`SNAME`,sco.`C_SCORE`,sco.`SORT` FROM 
student stu LEFT JOIN score sco ON stu.`ROW_ID` = sco.`SID` 


SELECT stu.`SNAME`,sco.`C_SCORE`,sco.`SORT` FROM 
student stu , score sco where stu.`ROW_ID` = sco.`SID` 


SELECT stu.`SNAME`,sco.`C_SCORE` FROM 
student stu LEFT JOIN score sco ON stu.`ROW_ID` = sco.`SID` 


SELECT sco.`C_SCORE` ,cou.`CNAME` FROM score sco  

 RIGHT JOIN course cou ON cou.`ROW_ID` = sco.`CID`




SELECT stu.`SNAME`,sco.`C_SCORE` ,cou.`CNAME` FROM