不一样的坚强

摘要： 1.IN 操作符 在业务密集的SQL当中尽量不采用IN操作符而使用EXISTS2.NOT IN 操作符 强列推荐不使用3. <> 操作符 强列推荐不使用 用其它相同功能的操作运算代替, 如 a<>0 改为 a>0 or a<0 ;a<>’’ 改为 a>’’4. > < 操作符 推荐5.... 阅读全文

摘要： set showplan_text ongoselect exported,money,count(1) num from cardwhere IsGived = 1group by exported,money;goset showplan_text offgoSET STATISTICS TIME ONGOSELECT COUNT（*） FROM titleauthersGOSET STATI... 阅读全文

摘要： Hash JoinWhen it comes to physical join operators, hash join does the heavy lifting. While nested loops join works well with relatively small data sets and merge join helps with moderately sized data ... 阅读全文