語句二:select * from pr04_pr05_su_jiao_原材料 with (nolock) where pr0501 like '%YMU5008' and pr0408 = '005' order by pr0504,pr0503 語句一:select * from pr04_pr05_su_jiao_原材料 with (nolock) where pr0501='YMU5008' and pr0408 = '005' order by pr0504,pr0503 )你改变一下顺序,在测试一边看看:-)
则第一句会利用索引,而第二句不会,因为第二句的like比较中,第一个是通配符,从而无法确定从那个位置开始检索数据.
理论上不会!
实际也不会!