假設某個表有一個聯合索引（c1,c2,c3,c4）一下——隻能使用該聯合索引的c1,c2,c3部分
A where c1=x and c2=x and c4>x and c3=x
B where c1=x and c2=x and c4=x order by c3
C where c1=x and c4= x group by c3,c2
D where c1=? and c5=? order by c2,c3
E where c1=? and c2=? and c5=? order by c2,c3
有誰知道下面A-E能否可以使用索引！！為什麼？
答案：自學it網-索引問題