几个sql案例

 

 

第一题
select 
Case When t.flag>0 Then "T" Else "F" End 
from 
(SELECT instr(TableA.col1,TableA.col2) as flag from TableA) t第三题
select s.* from student s ,(SELECT name,MAX(score) m from student GROUP BY name) t 
where 
s.name = t.name and s.score = t.m 
ORDER BY `name`第四题
select name, GROUP_CONCAT( 
CONCAT('{"',subject,'":',score,"}") 
)
from student GROUP BY name