摘要:
视图:把一个查询结果集当作表例:select * from (select * from score,grade where score.degree between low and upp) as jieguotable where rank='A' as 后面的作为一个虚拟的表create vi... 阅读全文
摘要:
一、多个条件查询:in、between select * from category where parent='013' or parent='12' or parent='011'等于select * from category where parent in ('011',''012','01... 阅读全文